なるへそ

interjection, adverb

I see; indeed; that's right

Slangy, humorous twist on なるほど. Used in casual conversation to show understanding or agreement, often with a playful tone.

See also: なるほど

• なるへそ、そういうことだったのか。

  I see, so that's what it was.

• A: この店みせ、実じつは深しん夜やまでやってるんだよ。B: なるへそ！

  A: This shop is actually open until late at night. B: I see!