i cheongbajineun nahante jal majayo.

는 is the topic marker. It shows that 이 청바지 is the thing being talked about.

So 이 청바지는 means something like:

• As for these jeans, ...
• These jeans, ...

In this sentence, it sets up these jeans as the topic, and then the rest of the sentence says how they are in relation to the speaker: they fit me well.

It can also add a slight contrast depending on context, such as:

• These jeans fit me well (maybe unlike some others).

Because with 맞다 meaning to fit / to suit, the person is usually marked with 한테, 에게, or sometimes 에 rather than as the grammatical subject.

So:

• 나한테 잘 맞아요 = it fits me well
• literally, something like to me, it fits well

This is different from English, where me is a direct object. In Korean, the person who is suited by something is often treated more like a recipient/target.

한테 means to or for when referring to a person, and in everyday speech it often sounds natural and conversational.

So:

• 나한테 = to me

In this sentence, it marks the person that the jeans fit.

Similar alternatives are:

• 나에게 — a bit more neutral or formal
• 저한테 — to me, but using the more polite 저

Yes, 잘 usually means well, but with 맞다 it often means fit well or suit well.

So:

• 잘 맞아요 = fits well
• not just is correct well, but specifically suits / fits nicely

You will often see 잘 with verbs where English uses a more natural phrase instead of a direct well:

• 옷이 잘 맞아요 = The clothes fit well
• 그 사람한테 잘 어울려요 = It looks good on that person

The dictionary form is 맞다.

In this sentence, 맞다 means:

• to fit
• to suit

The polite present form is:

• 맞다 → 맞아요

This is the standard polite ending used in everyday conversation.

Yes. 맞다 has several meanings, and context tells you which one is meant.

Common meanings include:

• to be correct
• to fit / suit
• to be hit in some contexts

In this sentence, because it is talking about jeans and me, the meaning is clearly:

• to fit

So 이 청바지는 나한테 잘 맞아요 means the jeans fit the speaker well, not that the jeans are correct.

Korean nouns usually do not have to show singular vs. plural the way English does.

So 청바지 can refer to:

• jeans
• a pair of jeans
• sometimes just jean pants as an item of clothing

Because English normally uses jeans as a plural-looking word, translations often say:

• These jeans fit me well

Even though Korean does not need a plural marker here.

Because Korean usually does not mark plural unless it is necessary.

들 can mark plurality, but it is often omitted, especially when the meaning is already obvious.

So:

• 이 청바지 is perfectly natural for these jeans / this pair of jeans
• 이 청바지들 would sound more like these jeans (multiple items/pairs)

In normal clothing situations, 청바지 alone is enough.

Yes. In many situations, 저한테 may be more appropriate.

Compare:

• 나한테 = to me, using 나 (plain/casual I)
• 저한테 = to me, using 저 (humble/polite I)

Since the sentence ends in the polite form 맞아요, many learners expect 저한테. That is often a very safe choice in polite conversation.

However, 나한테 can still appear if the speaker is talking in a generally polite style but uses 나 because of the relationship or tone.

Yes, that is also grammatical.

The difference is mainly about topic vs. subject focus:

• 이 청바지는 나한테 잘 맞아요
  = As for these jeans, they fit me well
• 이 청바지가 나한테 잘 맞아요
  = These jeans are the ones that fit me well

Very roughly:

• 는 sounds more topical and sometimes contrastive
• 가 sounds more like identifying or emphasizing the subject

Both are natural, but the nuance changes.

No, Korean word order is more flexible than English because particles show the grammatical roles.

So these can all work, depending on emphasis:

• 이 청바지는 나한테 잘 맞아요
• 나한테 이 청바지는 잘 맞아요
• 이 청바지가 나한테 잘 맞아요

The most neutral textbook-style version is often the original one, but changing the order can shift emphasis.

맞아요 is in the polite informal style, often called the 해요체 style.

It is very common in everyday Korean and is appropriate in many normal conversations.

Compare:

• 맞아 — casual
• 맞아요 — polite
• 맞습니다 — more formal

So this sentence is polite, but not stiff or highly formal.

No. 잘 맞다 can be used for several kinds of fit or suit.

For example:

• 이 신발은 나한테 잘 맞아요 = These shoes fit me well
• 이 안경은 제 얼굴에 잘 맞아요 = These glasses suit my face well
• 그 일은 저한테 잘 맞아요 = That job suits me well

So it can describe physical fit, personal suitability, or compatibility depending on the context.