🤷

Expressing Uncertainty: 잘 모르겠어요

Keywords
불확실
Lesson #
S
Done
Section
Basic Speaking
🦄
TL;DR 🦄
  • 🤷 잘 모르겠어요 [jal mo-reu-ge-sseo-yo] — "I don't really know"
  • ⏳ 아직 잘 모르겠어요 [a-jik jal mo-reu-ge-sseo-yo] — "I'm not sure yet"
  • ❓ 확실하지 않아요 [hwak-sil-ha-ji a-na-yo] — "It's not certain"
  • 🌀 ...인지 모르겠어요 [in-ji mo-reu-ge-sseo-yo] — "I don't know if/whether..."
  • 💬 글쎄요, 그건 모르겠네요 [geul-sse-yo, geu-geon mo-reu-gen-ne-yo] — "Well, I don't know about that"
🔊
🎧 Iru Helper Note: Hear every phrase in this lesson spoken aloud and practice your pronunciation with the Iru Helper Widgets.
 

🌈 The Big Picture

There's a small but important difference between 몰라요 [mol-la-yo] — "I don't know" (flat, plain) — and 모르겠어요 [mo-reu-ge-sseo-yo] — "I don't really know" (softer, more thoughtful). The -겠- adds a sense of "I've thought about it, and I genuinely can't say" — making it feel more humble and less abrupt. Adding 잘 [jal] ("well") softens it even further: 잘 모르겠어요 is the warmest, most natural way to say "I'm not sure" in everyday Korean.
  • A: 이거 어떻게 하는 거예요? — "How do you do this?"
  • B: 잘 모르겠어요. 한번 찾아볼게요 — "I'm not sure. Let me look it up"

🎭 -(으)ㄴ/는지 모르겠어요: "I Don't Know If..."

To express uncertainty about a specific question — "I don't know if/whether ___" — Korean uses -(으)ㄴ/는지 모르겠어요 [(eu)n/neun-ji mo-reu-ge-sseo-yo]. This pattern turns a yes/no or wh-question into an embedded clause of uncertainty.
  • 이게 맞는지 모르겠어요 — "I don't know if this is correct"
  • 내일 비가 올지 모르겠어요 — "I don't know if it'll rain tomorrow"
  • 어디서 사야 할지 모르겠어요 — "I don't know where I should buy it"
This is one of the most useful patterns for sounding natural when you're genuinely unsure — much more common in speech than a flat 모르겠어요 alone.

🧳 Essential Phrase Kit

  • 잘 모르겠어요 [jal mo-reu-ge-sseo-yo] — "I don't really know"
  • 아직 잘 모르겠어요 [a-jik jal mo-reu-ge-sseo-yo] — "I'm not sure yet"
  • 확실하지 않아요 [hwak-sil-ha-ji a-na-yo] — "It's not certain"
  • ...인지 모르겠어요 [in-ji mo-reu-ge-sseo-yo] — "I don't know if/whether..."
  • 글쎄요, 그건 모르겠네요 [geul-sse-yo, geu-geon mo-reu-gen-ne-yo] — "Well, I don't know about that"
  • 한번 찾아볼게요 [han-beon cha-ja-bol-ge-yo] — "Let me look it up"
  • 저도 헷갈려요 [jeo-do het-gal-lyeo-yo] — "I'm confused too"
  • 어떻게 해야 할지 모르겠어요 [eo-tteo-ke hae-ya hal-ji mo-reu-ge-sseo-yo] — "I don't know what to do"
  • 그건 저도 잘 몰라요 [geu-geon jeo-do jal mol-la-yo] — "I don't really know that either"
  • 확인해 봐야 할 것 같아요 [hwa-gin-hae bwa-ya hal geot ga-ta-yo] — "I think I need to check"

🛠️ Putting Together

A: 이 프로그램 어떻게 쓰는 거예요?
B: 음, 저도 잘 모르겠어요. 한번 찾아볼게요.
A: "How do you use this program?" B: "Hmm, I don't really know either. Let me look it up."
🦄 Grammar note: 잘 모르겠어요 followed by an offer like 한번 찾아볼게요 keeps the conversation constructive instead of just ending with "I don't know."
A: 내일 소풍 갈 수 있을까요?
B: 글쎄요, 내일 비가 올지 모르겠어요. 날씨 확인해 봐야 할 것 같아요.
A: "Will we be able to go on the picnic tomorrow?" B: "Well, I don't know if it'll rain tomorrow. I think I need to check the weather."
🦄 Grammar note: 비가 올지 모르겠어요 uses -(으)ㄹ지 모르겠어요 to express uncertainty about a future event.
A: 이 근처에 약국이 어디 있는지 아세요?
B: 어... 저도 헷갈려요. 이 길이 맞는지 잘 모르겠어요. 지도 한번 볼까요?
A: "Do you know where a pharmacy is around here?" B: "Uh... I'm confused too. I'm not sure if this is the right way. Should we check the map?"
🦄 Grammar note: 맞는지 모르겠어요 — "I don't know if it's correct" — pairs well with 헷갈려요 ("I'm confused") when you're unsure about directions or information.

🗣️ Speaking Practice: Mini Dialogue

민수: 지은 씨, 이번 주 토요일에 시간 괜찮아요? 같이 등산 갈까 했는데요.
[ji-eun ssi, i-beon ju to-yo-i-re si-gan gwaen-cha-na-yo? ga-chi deung-san gal-kka hae-sseon-de-yo]
"Jieun, are you free this Saturday? I was thinking we could go hiking together."
지은: 음, 아직 잘 모르겠어요. 그날 약속이 있을 수도 있어서요.
[eum, a-jik jal mo-reu-ge-sseo-yo. geu-nal yak-so-gi i-sseul su-do i-sseo-seo-yo]
"Hmm, I'm not sure yet. I might have plans that day."
민수: 그렇군요. 언제쯔음 알 수 있을까요?
[geu-reo-kun-yo. eon-je-jjeum al su i-sseul-kka-yo?]
"I see. About when would you be able to know?"
지은: 내일까지는 확인해 볼게요. 그리고 날씨도 괜찮을지 모르겠어요.
[nae-il-kka-ji-neun hwa-gin-hae bol-ge-yo. geu-ri-go nal-ssi-do gwaen-cha-neul-ji mo-reu-ge-sseo-yo]
"I'll check by tomorrow. And I'm also not sure if the weather will be okay."
민수: 맞아요, 그것도 확인해 봐야 할 것 같아요. 일단 기다려 볼게요.
[ma-ja-yo, geu-geot-do hwa-gin-hae bwa-ya hal geot ga-ta-yo. il-dan gi-da-ryeo bol-ge-yo]
"Right, I think we need to check that too. I'll wait for now."
지은: 네, 확인하고 바로 연락할게요!
[ne, hwa-gin-ha-go ba-ro yeol-la-kal-ge-yo]
"Okay, I'll check and contact you right away!"

🧭 Speaking Tip

In Korean, admitting you don't know something isn't a failure — how you say it matters more than the fact itself. Plain 몰라요 can sound curt, even rude, especially to someone older or in a formal setting. 잘 모르겠어요 softens it with humility, and following up with 확인해 볼게요 or 찾아볼게요 shows you're willing to find out. This combination — admitting uncertainty + offering to follow up — is the natural Korean way to handle "I don't know" gracefully.

⚠️ Pitfalls to Dodge

  • ❌ Using plain 몰라요 by itself — it can sound blunt or even dismissive; 잘 모르겠어요 is much softer.
  • ❌ Leaving uncertainty unresolved — pair 모르겠어요 with a next step like 확인해 볼게요 or 찾아볼게요 to stay constructive.
  • ❌ Mixing up the tense of -지 모르겠어요 — use -(으)ㄹ지 for future guesses, -는지 for present, -(으)ㄴ지 for past.
  • ❌ Overusing 글쎼요 to avoid giving an answer — repeated too often, it can come across as evasive rather than thoughtful.
You're ready to express uncertainty naturally and gracefully — 화이팅! 🤷✨
 
Try this exercise
Instructions: For each prompt, write your response in Korean using the patterns from this lesson. Then check the toggle below for a sample answer.
1. Say "I don't really know."
Answer
잘 모르겠어요. (I don't really know.)
2. Say "I'm not sure yet."
Answer
아직 잘 모르겠어요. (I'm not sure yet.)
3. Say "It's not certain."
Answer
확실하지 않아요. (It's not certain.)
4. Say "I don't know if it'll rain tomorrow" (내일 비가 오다, future).
Answer
내일 비가 올지 모르겠어요. (I don't know if it'll rain tomorrow.)
5. Say "Well, I don't know about that."
Answer
글쎼요, 그건 모르겠네요. (Well, I don't know about that.)
6. Say "Let me look it up."
Answer
한번 찾아볼게요. (Let me look it up.)
7. Say "I'm confused too."
Answer
저도 헷갈려요. (I'm confused too.)
8. Say "I don't know what to do" (어떻게 하다).
Answer
어떻게 해야 할지 모르겠어요. (I don't know what to do.)
9. Say "I don't really know that either."
Answer
그건 저도 잘 몰라요. (I don't really know that either.)
10. Say "I think I need to check" (확인하다).
Answer
확인해 봐야 할 것 같아요. (I think I need to check.)
📚
Vocabulary Box
  • 모르다 — to not know
  • 확실하다 — to be certain
  • 헷갈리다 — to be confused, mixed up
  • 찾아보다 — to look up, search for
  • 확인하다 — to check, confirm
  • 소풍 — picnic, outing
  • 등산 — hiking
  • 약속 — appointment, plan
  • 언제쯔음 — around when
  • 연락하다 — to contact
Pitfalls 💡
  • 몰라요 alone sounds curt — add 잘.
  • Follow up with 확인해 볼게요/찾아볼게요.
  • -지 모르겠어요 tense changes with context.
🚀
Want more reps? Head to the Practice Hub below for three full exercise sets!
 
📦
🎯 Practice Hub — Expressing Uncertainty: 잘 모르겠어요
Work through these three exercises to practice expressing uncertainty naturally and gracefully. Try answering out loud before checking each answer — and use the Iru Helper Widgets above if you want to hear the pronunciation again.

Exercise 1 — Basic Uncertainty Phrases 🤷

A. Say "I don't really know."
Answer
잘 모르겠어요. [jal mo-reu-ge-sseo-yo]
B. Say "I'm not sure yet."
Answer
아직 잘 모르겠어요. [a-jik jal mo-reu-ge-sseo-yo]
C. Say "It's not certain."
Answer
확실하지 않아요. [hwak-sil-ha-ji a-na-yo]
D. Say "I'm confused too."
Answer
저도 헷갈려요. [jeo-do het-gal-lyeo-yo]
E. Say "Let me look it up."
Answer
한번 찾아볼게요. [han-beon cha-ja-bol-ge-yo]
F. Say "I think I need to check."
Answer
확인해 봐야 할 것 같아요. [hwa-gin-hae bwa-ya hal geot ga-ta-yo]
G. Say "I don't really know that either."
Answer
그건 저도 잘 몰라요. [geu-geon jeo-do jal mol-la-yo]
H. Say "Well, I don't know about that" (글쎼요).
Answer
글쎼요, 그건 모르겠네요. [geul-sse-yo, geu-geon mo-reu-gen-ne-yo]
I. Say "I don't know what to do."
Answer
어떻게 해야 할지 모르겠어요. [eo-tteo-ke hae-ya hal-ji mo-reu-ge-sseo-yo]
J. Say "I'll check and contact you right away."
Answer
확인하고 바로 연락할게요. [hwa-gin-ha-go ba-ro yeol-la-kal-ge-yo]
📚
Quick Reference
  • 잘 모르겠어요 — I don't really know
  • 확실하지 않아요 — not certain
  • 헷갈려요 — I'm confused
  • 찾아볼게요 — let me look it up
  • 확인해 볼게요 — let me check

Exercise 2 — Using -지 모르겠어요 🌀

A. Say "I don't know if this is correct" (이게 맞다).
Answer
이게 맞는지 모르겠어요.
B. Say "I don't know if it'll rain tomorrow."
Answer
내일 비가 올지 모르겠어요.
C. Say "I don't know where I should buy it" (어디서 사다).
Answer
어디서 사야 할지 모르겠어요.
D. Say "I'm also not sure if the weather will be okay" (괜찮다, future).
Answer
날씨도 괜찮을지 모르겠어요.
E. Say "I don't know if I'm free this Saturday" (시간이 있다).
Answer
이번 주 토요일에 시간이 있을지 모르겠어요.
F. Say "I don't know if this is the right way" (이 길이 맞다).
Answer
이 길이 맞는지 모르겠어요.
G. Say "I don't know if I should go" (가다, future).
Answer
가야 할지 모르겠어요.
H. Say "I don't know if he already left" (벌써 갔다, past).
Answer
벌써 갔는지 모르겠어요.
I. Say "I don't know if it's expensive" (비싸다).
Answer
비싼지 모르겠어요.
J. Say "I don't know if it's possible" (가능하다).
Answer
가능한지 모르겠어요.
📚
Quick Reference
  • -(으)ㄹ지 모르겠어요 — future "I don't know if"
  • -는지 모르겠어요 — present "I don't know if"
  • -(으)ㄴ지 모르겠어요 — past "I don't know if"
  • 가능하다 — to be possible
  • 벌써 — already

Exercise 3 — Full Uncertainty Conversations 💬

A. "이번 주 토요일에 시간 괜찮아요?" — What does this mean?
Answer
"Are you free this Saturday?"
B. Respond with "Hmm, I'm not sure yet. I might have plans that day."
Answer
음, 아직 잘 모르겠어요. 그날 약속이 있을 수도 있어서요.
C. Say "About when would you be able to know?"
Answer
언제쯔음 알 수 있을까요?
D. Say "I'll check by tomorrow."
Answer
내일까지는 확인해 볼게요.
E. Say "And I'm also not sure if the weather will be okay."
Answer
그리고 날씨도 괜찮을지 모르겠어요.
F. Say "Right, I think we need to check that too."
Answer
맞아요, 그것도 확인해 봐야 할 것 같아요.
G. Say "I'll wait for now."
Answer
일단 기다려 볼게요.
H. Say "Do you know where a pharmacy is around here?"
Answer
이 근처에 약국이 어디 있는지 아세요?
I. Respond with "Uh... I'm confused too. I'm not sure if this is the right way."
Answer
어... 저도 헷갈려요. 이 길이 맞는지 잘 모르겠어요.
J. Say "Should we check the map?"
Answer
지도 한번 볼까요?
📚
Cheat Sheet
  • 잘 모르겠어요 — I don't really know
  • 아직 잘 모르겠어요 — not sure yet
  • -지 모르겠어요 — I don't know if/whether
  • 확인해 볼게요 — I'll check
  • 헷갈려요 — confused
  • 약속이 있다 — to have plans
🎉 잘했어요! You can now express uncertainty naturally and gracefully in Korean!