ginjanghaeseo bimireul malhae beoryeosseoyo.

긴장해서 comes from 긴장하다, which means to be nervous or to get tense.

Here, -아서/어서 is attached to show a reason or cause, so 긴장해서 means:

• because I was nervous
• being nervous
• I got nervous and so...

In this sentence, it connects naturally to the next action:

• 긴장해서 비밀을 말해 버렸어요
• Because I was nervous, I ended up telling the secret

So -해서 is explaining why the speaker said the secret.

Great question. 긴장 is indeed a noun meaning tension or nervousness, and when you add 하다, it becomes a verb:

• 긴장 = tension, nervousness
• 긴장하다 = to be nervous / to feel tense

This is very common in Korean. Many words of this type work like this:

• 공부
  • 하다 = 공부하다 = to study
• 운동
  • 하다 = 운동하다 = to exercise
• 긴장
  • 하다 = 긴장하다 = to be nervous

So even though it comes from a noun, the full form behaves like a verb.

비밀 means secret, and 을 is the object marker.

So:

• 비밀 = secret
• 비밀을 = the secret / a secret (as the thing being spoken)

The verb 말하다 can take something as its object when it means to say or to tell something:

• 사실을 말하다 = to tell the truth / say the facts
• 이름을 말하다 = to say one’s name
• 비밀을 말하다 = to tell a secret

Because 비밀 ends in a consonant, it takes 을 rather than 를.

This is one of the most important parts of the sentence.

말해 버렸어요 uses the grammar -아/어 버리다, which often adds a feeling like:

• something was done completely
• it happened unintentionally
• the speaker regrets it
• it slipped out
• it’s done and can’t be taken back

So:

• 말했어요 = I said it / I told it
• 말해 버렸어요 = I blurted it out / I ended up telling it / I told it and now it’s done

In this sentence, 버렸어요 strongly suggests that the speaker did not really mean to reveal the secret, or at least regrets having done so.

Not always.

-아/어 버리다 can have a few related meanings:

1. Completion

   • the action is fully finished
   • example: 다 먹어 버렸어요 = I ate it all up

2. Unintended result / accident

   • example: 잊어버렸어요 = I forgot

3. Regret / frustration / “oh no” feeling

   • example: 비밀을 말해 버렸어요 = I ended up telling the secret

So in this sentence, the most natural feeling is regret or accidentally letting it slip, but the deeper idea is that the action is done completely and cannot be undone.

Yes, there is a slight difference.

• 말하다 = to say, to tell
• 이야기하다 = to talk, to tell a story, to discuss

In this sentence, 말하다 fits better because the speaker is referring to a specific piece of information being revealed: the secret.

• 비밀을 말하다 sounds like to tell the secret
• 비밀을 이야기하다 is possible in some contexts, but it can sound more like talk about the secret rather than let the secret out

So 말하다 is the better choice for the idea of blurting out confidential information.

Korean often leaves out the subject when it is obvious from context.

In this sentence, the understood subject is usually I:

• (제가) 긴장해서 비밀을 말해 버렸어요
• I was nervous and ended up telling the secret

The person who was nervous is normally the same person who told the secret, because the first clause and the second clause are naturally connected.

Korean does this all the time, especially in conversation, if the listener can easily guess who the subject is.

It is in the past tense polite form.

Let’s break it down:

• 말하다 = to say
• 말해 버리다 = to end up saying / to blurt out
• 말해 버렸어요 = ended up saying / blurted out

The past tense comes from 버리다 → 버렸어요.

So the sentence describes something that already happened:

• I ended up telling the secret
• I blurted out the secret

Yes. You may see both:

• 말해 버렸어요
• 말해버렸어요

In grammar explanations, it is often written with a space so learners can clearly see the helper verb 버리다.

In real writing, it is very common to write it attached:

• 말해버렸어요

Both are understood, and both represent the same grammar pattern -아/어 버리다.

Both can work, but they feel slightly different.

• 긴장해서 = because I was nervous / because I got tense
• 긴장돼서 = because I felt nervous

긴장하다 focuses on the state/action of becoming tense or being nervous.

긴장되다 is more like to become nervous or to feel nervous, often with a slightly more passive or natural-emotional feel.

In everyday speech, both are common, and in many situations the difference is small. But 긴장해서 비밀을 말해 버렸어요 sounds very natural and straightforward.

-아서/어서 can sometimes feel like a simple connection between actions, but in this sentence it is most naturally understood as because.

So while literally it connects the two parts:

• 긴장해서
  • 비밀을 말해 버렸어요

the actual meaning is:

• Because I was nervous, I ended up telling the secret

The cause-and-result relationship is very strong here. Being nervous explains why the speaker blurted out the secret.

It is in the polite informal style, often called -아요/어요 style.

That means it is polite enough for:

• everyday conversation
• speaking to someone you do not know very well
• speaking politely without being formal or stiff

Compare:

• 말해 버렸어요 = polite
• 말해 버렸습니다 = more formal
• 말해 버렸어 = casual, plain conversation with someone close

So the sentence sounds polite and natural in normal speech.

Yes, very strongly.

That implication mainly comes from -아/어 버리다.

Without that grammar, the sentence would just report the action:

• 긴장해서 비밀을 말했어요 = I told the secret because I was nervous

But with 말해 버렸어요, it sounds more like:

• I blurted out the secret
• I let the secret slip
• I ended up telling the secret

So the sentence often carries the feeling that it was not planned, and the speaker may regret it.