건 알겠는데

I understand that, but

→ 것+은
phrase Rare #29,281
I understand that, but 건 is a contraction of 것은. This phrase acknowledges something before introducing a contrasting point.
KO: 네가 바쁜 건 알겠는데, 잠깐 도와줄 수 있어?
EN: I understand that you're busy, but could you help for a moment?

록조가 자기 혼혈 자식을 찾고 있는 건 알겠는데 엄마 곰은 어디 있습니까?

I understand that Rockzo is looking for his mixed-race child, but where is the mother bear?

— 원 배틀 애프터 어나더 (2025)

좋은 분 인 건 알겠는데 모두가 구세주 타입은 아니에요

I know you’re a good person, but not everyone is the kind of person who plays savior.

— 데드풀과 울버린 (2024)

네가 요즘 기분 거지 같은 건 알겠는데 야, 아무리 그래도… 하긴…

I know you've been feeling like crap lately, but come on, even so… Well, I guess…

— Dream (2023)