eonnineun boksungaboda gyureul deo johahajiman, jeoneun podoga jeil johayo.

언니 literally means older sister, but it is used by a female speaker. It can also be used for an older female friend or someone close, not only a biological sister.

So in this sentence, the speaker is most naturally understood as female. If a male speaker were talking about his older sister, he would usually say 누나 instead.

-는 is the topic marker. It marks what the sentence is talking about and often adds a sense of contrast.

So:

• 언니는 = as for my older sister
• 저는 = as for me

In this sentence, that contrast is very important:

• My older sister likes tangerines more than peaches,
• but I like grapes best.

Using -는 helps set up that comparison between two people.

Korean object particles change shape depending on whether the noun ends in a vowel or a consonant.

• after a consonant: -을
• after a vowel: -를

귤 ends in the consonant sound ㄹ, so it takes -을 → 귤을

For comparison:

• 사과를 because 사과 ends in a vowel
• 빵을 because 빵 ends in a consonant

The same kind of pattern happens with other particles too:

• 은/는
• 이/가
• 을/를

-보다 means than when making a comparison.

So:

• 복숭아보다 = than peaches
• 사과보다 = than apples
• 저보다 = than me

In this sentence:

• 복숭아보다 귤을 더 좋아해요
  = likes tangerines more than peaches

A very common comparison pattern is:

• A보다 B를 더 좋아하다
  = to like B more than A

더 means more.

In Korean, when you compare two things, it is very common to use both:

• A보다 = than A
• 더 = more

So:

• 복숭아보다 귤을 더 좋아해요
  = likes tangerines more than peaches

Without 더, the sentence can sometimes still be understood from context, but 더 is the normal and clearer way to show comparison.

좋아하지만 comes from 좋아하다 + -지만.

• 좋아하다 = to like
• -지만 = but / although

So:

• 좋아하지만 = likes ..., but ...

It connects the first clause to the second clause.

Here the structure is:

• 언니는 복숭아보다 귤을 더 좋아하지만, 저는 ...
• My older sister likes tangerines more than peaches, but I ...

This -지만 ending is a very common way to join two contrasting ideas in one sentence.

저 is the polite/humble word for I, while 나 is more casual.

Since the sentence ends in polite style with 좋아요, using 저는 matches that level of politeness naturally.

So:

• 저는 = polite
• 나는 = casual

You will often see:

• polite sentence → 저는
• casual sentence → 나는

This is a very common question, because both are possible, but they work a little differently.

In the first clause, the sentence uses 좋아하다:

• 귤을 더 좋아하지만
• likes tangerines more

Here, 귤 is the object, so it takes -을.

But in the second clause, the sentence uses 좋다 in the form 좋아요:

• 포도가 제일 좋아요

Literally, this is closer to:

• grapes are the most good/pleasing

But in natural English, it means:

• I like grapes the best

So 포도 takes -가 here because it is treated as the subject of 좋아요.

Both of these are natural:

• 포도를 제일 좋아해요
• 포도가 제일 좋아요

The version in your sentence is very common in everyday Korean.

제일 means the most or best.

It is used for the superlative, not just a comparison between two things.

So:

• 더 = more
• 제일 = most

Compare these:

• 복숭아보다 귤을 더 좋아해요
  = likes tangerines more than peaches
• 포도가 제일 좋아요
  = likes grapes the best / grapes are the most liked

A similar word is 가장. In everyday speech, 제일 is extremely common.

They are related, but not the same.

• 더 is for a comparison between things: more
• 제일 is for the highest degree: most / best

So in this sentence:

• 더 좋아하지만 compares tangerines and peaches
• 제일 좋아요 says grapes are the top choice

You can think of it like this:

• 더 = comparative
• 제일 = superlative

Korean word order is different from English, and particles help show each word’s role.

The sentence breaks down like this:

• 언니는 = as for my older sister
• 복숭아보다 = than peaches
• 귤을 = tangerines
• 더 = more
• 좋아하지만 = likes, but
• 저는 = as for me
• 포도가 = grapes
• 제일 = the most
• 좋아요 = are good / I like

So the literal flow is roughly:

• As for my older sister, than peaches, tangerines more likes, but as for me, grapes are the most pleasing.

That sounds unnatural in English, but it is normal Korean structure. Korean often puts the main verb or adjective at the end of the clause.