eonniga bonaen mesijireul jigeum hwaginhaeyo.

언니 means older sister, but it is also commonly used by a woman to address or refer to an older female she is close to, such as a friend or acquaintance.

A key point:

• Women/girls use 언니 for an older female.
• Men/boys do not use 언니 that way.

For comparison:

• a man referring to his older sister would usually say 누나
• a woman referring to her older brother would say 오빠
• a man referring to his older brother would say 형

So in this sentence, the speaker is probably female, or at least the sentence is written from the perspective of someone who uses 언니.

가 is the subject marker, so 언니가 means older sister / unni is the one who did the sending.

Here, the sentence is focusing on who sent the message:

• 언니가 보낸 메시지 = the message that unni sent

If you used 언니는, it would sound more like you are introducing or contrasting 언니 as a topic:

• 언니는 보낸 메시지... would not fit naturally in this exact structure

So 가 is used because 언니 is functioning as the subject inside the descriptive clause 보낸.

In Korean, clauses that describe a noun come before the noun.

So:

• 언니가 보낸 메시지 literally works like:
• unni-sent message or more naturally:
• the message that unni sent

This is very common in Korean. Instead of saying:

• the message that unni sent

Korean says:

• unni sent message

More examples:

• 제가 만든 음식 = the food I made
• 어제 본 영화 = the movie I saw yesterday
• 친구가 준 선물 = the gift my friend gave me

보내다 is the dictionary form, meaning to send.

When a verb describes a noun in the past, Korean often changes it into a form like -(으)ㄴ.

So:

• 보내다 → stem 보내-
• past descriptive form → 보낸
• 보낸 메시지 = the message that was sent / the message someone sent

This form is not a full past-tense sentence by itself. It is specifically being used to modify the noun 메시지.

Compare:

• 언니가 메시지를 보냈어요. = Unni sent a message.
• 언니가 보낸 메시지 = the message that unni sent

를 is the object marker.

In this sentence, the thing being checked is the message, so:

• 메시지 = message
• 메시지를 = the message + object marker

The main verb is 확인해요 = check / am checking, and what is being checked?

• 언니가 보낸 메시지

So the structure is:

• [언니가 보낸 메시지]를 지금 확인해요
• I am checking the message unni sent now

지금 means now / right now.

In this sentence:

• 지금 확인해요 = check now / am checking now

Its position is flexible. Korean adverbs often move around more freely than in English, as long as the sentence still sounds natural.

Possible variations:

• 언니가 보낸 메시지를 지금 확인해요.
• 지금 언니가 보낸 메시지를 확인해요.

Both are natural, though the emphasis may shift slightly:

• putting 지금 earlier can emphasize the time more
• putting it before the verb is also very common

확인하다 is the dictionary form, meaning to check / to confirm.

In an actual sentence, it usually changes form.
확인해요 is the polite present-style form.

Breakdown:

• 확인하다 = to check
• 확인해요 = check / am checking / do check

This style is very common in everyday Korean because it is polite without being overly formal.

Compare:

• 확인한다 = plain style
• 확인해요 = polite everyday style
• 확인합니다 = more formal polite style

Korean present-form verbs can cover several meanings that English separates.

So 확인해요 can mean:

• check
• am checking
• sometimes even will check, depending on context

With 지금, the most natural interpretation is:

• am checking right now

So although the Korean verb is not a special progressive form, the adverb 지금 strongly suggests an action happening now.

Yes, 언니가 보낸 메시지를 지금 확인하고 있어요 is also possible.

Difference:

• 확인해요 can simply state the action in a general present sense, and with 지금 it often means I’m checking it now
• 확인하고 있어요 more explicitly emphasizes the action is in progress

So:

• 확인해요 = natural and common
• 확인하고 있어요 = more explicitly I am in the middle of checking it

In many real situations, both are fine.

This is a very common Korean pattern.

확인 is a noun meaning something like confirmation/checking, and 하다 means to do. Together:

• 확인하다 = to check / to confirm

Many Korean verbs work this way, especially words of Sino-Korean origin.

Examples:

• 공부하다 = to study
• 전화하다 = to call
• 시작하다 = to start
• 준비하다 = to prepare

So 확인해요 is one of many very common noun + 하다 verbs.

Yes, that is the most natural understanding.

Things Korean leaves implicit:

• the subject I is omitted
• English would usually include I am
• Korean often does not mention the subject when it is obvious from context

So the full sense is something like:

• I’m checking the message that unni sent right now.

This omission of the subject is extremely common in Korean and does not make the sentence incomplete.