얼마나 찾았는지

how much I searched

→ 얼마나
phrase Rare #16,296
how much I searched Used in an embedded question or exclamation to emphasize the extent or duration of searching. The ending -는지 often means “whether” or introduces an indirect question; in these examples, the phrase can mean “how much I looked for you.”
KO: 내가 너를 얼마나 찾았는지 알아?
EN: Do you know how much I looked for you?

시간도 없는데 내가 당신을 얼마나 찾았는지 알아요?

Do you know how much I’ve been looking for you, even though I don’t have any time?

— 택시운전사 (2017)

얼마나 찾았는지 알아?

Do you know how long I've been looking for you?

— 세 얼간이 (2009)

얼마나 찾았는지 몰라요

You have no idea how long I’ve been looking for it.

— 8과 1/2 (1963)