chinguneun choyeone gwansimi eobseo.

는 is the topic marker. It makes 친구는 mean something like as for my friend or regarding my friend.

So the sentence is not just naming the subject mechanically; it is setting friend up as the topic and then saying something about that topic.

There can also be a slight contrastive feeling:

• 친구는 초연에 관심이 없어. = My friend, at least, isn’t interested in the premiere.

In many contexts, though, it just sounds natural and neutral.

If you used 친구가 instead, the sentence would focus more on who is not interested.

With 관심이 있다/없다 (to be interested / not interested), Korean normally uses 에 with the thing someone is interested in.

So the pattern is:

• N에 관심이 있다 = to have interest in N
• N에 관심이 없다 = to have no interest in N

That is why you get:

• 초연에 관심이 없어 = is not interested in the premiere

Using 을/를 here would not be the normal pattern.

Because 관심이 없다 is built around the idea of interest existing or not existing.

Literally, 없다 means to not exist / to not have. So 관심이 없어 is basically:

• interest does not exist
• or more naturally, there is no interest

That is why 관심 takes 이/가, not 을/를.

A useful way to remember it is:

• 초연에 관심이 있어. = There is interest in the premiere.
• 초연에 관심이 없어. = There is no interest in the premiere.

Very literally, it means there is no interest.

So the whole sentence is closer to:

• As for my friend, there is no interest in the premiere.

Natural English turns that into:

• My friend isn’t interested in the premiere.

This is a very common Korean way to express feelings or states: instead of saying someone actively does not interest, Korean often says a relevant noun exists or does not exist.

Yes. 없어 is the plain/casual form of 없다.

Levels:

• 없어 = casual
• 없어요 = polite
• 없습니다 = formal

So the same sentence can become:

• 친구는 초연에 관심이 없어요. = polite
• 친구는 초연에 관심이 없습니다. = formal

The version with 없어 is what you would use with friends, people younger than you, or in casual narration.

Korean often leaves things like my, your, or the unstated when they are clear from context.

So 친구는 could mean:

• my friend
• the friend
• a friend
• sometimes even my/our friend

In real usage, context tells you which one is meant.

English usually forces you to choose one, but Korean often does not.

Yes, N에 관심이 있다/없다 is a very common and productive pattern.

You can use it with many nouns:

• 음악에 관심이 있어. = I’m interested in music.
• 정치에 관심이 없어. = I’m not interested in politics.
• 한국 역사에 관심이 있어. = I’m interested in Korean history.

So in your sentence, 초연에 관심이 없어 follows a very standard grammar pattern.

To some extent, yes. Korean word order is more flexible than English, especially with particles marking each role.

For example, these are possible depending on emphasis:

• 친구는 초연에 관심이 없어.
• 초연에 친구는 관심이 없어.

Both can work, though the first is the most neutral and natural in many contexts.

What should stay the same is the grammatical relationship:

• 친구는 = topic
• 초연에 = target of interest
• 관심이 없어 = no interest

So you should think less in terms of strict English-style word order and more in terms of what each particle is marking.

A natural pronunciation is roughly:

• 초연에 → 초여네
• 관심이 → 관시미
• 없어 → 업써

So the whole second part may sound like:

• 초여네 관시미 업써

This happens because Korean pronunciation changes naturally across syllables in connected speech.

The spelling stays the same, but the spoken form becomes smoother.

The dictionary-style form is:

• 친구는 초연에 관심이 없다.

That is the basic plain-form sentence you would see in dictionaries or textbooks.

From that:

• 없다 → dictionary form
• 없어 → casual spoken form
• 없어요 → polite spoken form

So your sentence is simply the casual spoken version of 친구는 초연에 관심이 없다.