Expectations in Korean || With 었어야 했다 & 줄 몰랐다

Q: What does 었어야 했다 mean in Korean?

었어야 했다 expresses regret or unmet expectations about a past action — similar to "should have" in English. For example: 일찍 출발했어야 했어요. → "I should have left early."

Q: Can I use 줄 몰랐다 with verbs and adjectives?

Yes, you can! -줄 몰랐다 means "I didn’t know that..." and works with both verbs and adjectives. For example: 그 사람이 한국어를 잘하는 줄 몰랐어요. → "I didn’t know that person spoke Korean well."

Q: What the difference with 었어야 했다 and 아야 했다?

They both express obligation or regret, but 았/었어야 했다 is the correct full form to express "should have." 아야 했다 is not a standard past regret form and may be a mix-up with other structures.

Q: Can 줄 몰랐다 be used in the present tense?

No, 줄 몰랐다 refers to a past realization. It means that at some point you didn’t know something but you know it now. For present or future assumptions, you'd use different grammar.

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FULFILLED & UNFULFILLED EXPECTATIONS IN KOREAN

Expectations are a fundamental part of human communication. They reflect our beliefs about what should or will happen.

In Korean, expressing these expectations, especially when they are either met or unmet, requires a grasp of specific grammatical patterns.

UNFULFILLED OBLIGATIONS / REGRETS

This grammatical structure translates to should have done or ought to have done.

It’s used to express regret or a sense of obligation that was not fulfilled.

When we use this, we are looking back on a situation and indicating that a different action would have been more appropriate.

PATTERN

[Verb stem] + -았/었어야 했다

-았- is used after verb stems ending in ㅏ or ㅗ.
-었- is used after verb stems ending in other vowels.
-했- is used after 하다 verbs

Examples, Referring to cleaning the house:

청소했어야 했다

_{I should have cleaned.}

View More Examples:

설거지했어야 했다	I should have done the dishes.
빨래했어야 했다	I should have done the laundry.
장보러 갔어야 했다	I should have gone grocery shopping.
수리했어야 했다	I should have repaired it.

Nuances:
- This phrase often carries a tone of regret or self-reproach.
- It implies that the speaker recognizes their failure to meet an expected obligation.
- For example, “방을 정리했어야 했다” “I should have organized the room.” implies the room is still messy, and the speaker regrets not organizing it.

FULFILLED EXPECTATIONS / MISUNDERSTANDINGS

This structure translates to “I thought that…” It’s used to express an expectation or belief that was either correct or incorrect. It’s often used to express a past assumption.

PATTERN

[Verb stem] + -을/ㄹ 줄 알았다

-을 줄 알았다 is used after verb stems ending in a consonant.
-ㄹ 줄 알았다 is used after verb stems ending in a vowel.

깨끗할 줄 알았어요

_{I thought it would be clean.}

View More Examples:

빨리 끝날 줄 알았어요	I thought it would finish quickly.
도와줄 줄 알았어요	I thought you would help.
청소 다 한 줄 알았어요	I thought the cleaning was all done.
설거지 다 된 줄 알았어요	I thought the dishes were all washed.

Nuances:
- This phrase can indicate both fulfilled and unfulfilled expectations.
- If the expectation was correct, it expresses a confirmation of the speaker’s belief.
- If the expectation was incorrect, it expresses a misunderstanding or surprise.
- For example, if you enter a room, and it is very clean, you can say “깨끗할 줄 알았어요.” If the room is dirty you can say “깨끗할 줄 알았는데, 아니였어요.” “I thought it would be clean, but it wasn’t.”

UNFORESEEN CIRCUMSTANCES

This structure translates to I didn’t know that… It’s used to express a lack of knowledge or awareness about a situation. It highlights an unexpected outcome.

PATTERN

[Verb stem] + -을/ㄹ 줄 몰랐다

-을 줄 몰랐다 is used after verb stems ending in a consonant.
-ㄹ 줄 몰랐다 is used after verb stems ending in a vowel.

이렇게 더러울 줄 몰랐어요

_{I didn’t know it would be this dirty.}

View More Examples:

이렇게 오래 걸릴 줄 몰랐어요	I didn’t know it would take this long.
청소해야 할 줄 몰랐어요	I didn’t know I had to clean.
설거지해야 할 줄 몰랐어요	I didn’t know I had to wash the dishes.
쓰레기를 버려야 할 줄 몰랐어요	I didn’t know I had to throw out the trash.

Nuances:
- This phrase emphasizes the speaker’s surprise or lack of prior knowledge.
- It can also imply a sense of being unprepared or uninformed.
- For example, if someone asks you to clean the bathroom, and you did not know it needed to be cleaned, you can say:

^{hwajangsil cheongsohaeya hal jul mollasseoyo}

화장실 청소해야 할 줄 몰랐어요

_{I did not know I had to clean the bathroom}

PUTTING IT ALL TOGETHER

Let’s combine these structures with the vocabulary from house chores to illustrate how they work in context:

어제 방을 청소했어야 했는데, 너무 피곤해서 못 했어요	I should have cleaned my room yesterday, but I was too tired, so I couldn’t. (Regret)
집이 깨끗할 줄 알았는데, 먼지가 너무 많았어요	I thought the house would be clean, but there was too much dust.” (Unfulfilled expectation)
설거지를 이렇게 오래 해야 할 줄 몰랐어요	I didn’t know I had to do the dishes for this long. (Lack of awareness)
빨래를 다 널어 놓을 줄 알았는데, 아직 남았어요	I thought all of the laundry would be hung up to dry, but there is still some left. (Unfulfilled expectation.)
쓰레기통을 비웠어야 했는데, 깜빡했어요	I should have emptied the trashcan, but I forgot. (Regret)

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FAQs

What does 었어야 했다 mean in Korean?

었어야 했다 expresses regret or unmet expectations about a past action — similar to “should have” in English. For example: 일찍 출발했어야 했어요. → “I should have left early.”

Can I use 줄 몰랐다 with verbs and adjectives?

Yes, you can! -줄 몰랐다 means “I didn’t know that…” and works with both verbs and adjectives.

For example: 그 사람이 한국어를 잘하는 줄 몰랐어요. → “I didn’t know that person spoke Korean well.”

What the difference with 었어야 했다 and 아야 했다?

They both express obligation or regret, but 았/었어야 했다 is the correct full form to express “should have.” 아야 했다 is not a standard past regret form and may be a mix-up with other structures.

Can 줄 몰랐다 be used in the present tense?

No, 줄 몰랐다 refers to a past realization. It means that at some point you didn’t know something but you know it now.

For present or future assumptions, you’d use different grammar.

Can I use 었어야 했는데 instead of 었어야 했다?

Yes!

Adding 는데 makes the tone softer or adds a nuance like “but I didn’t.”

For example: 더 열심히 공부했어야 했는데… → “I should have studied harder (but I didn’t).”

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