의심해서 나쁠 건 없다 There is no harm in doubting A: 저 남자 너무 괜찮지 않아? Isn't that guy so handsome? B: 잘생긴 건 알겠는데 모르는 사람이니까 조심해. I know he's handsome, but you don't know him. Be careful. A: 성격도 좋을 것 같은데? I think he has a good personality, too. B: 의심해서 나쁠 건 없지. There is no harm in doubting.