알랑가몰라 This includes Korean dialect. In formal language, we'd say 알려나 몰라, which means 'I'm not sure if you'd know this.' 왜 화끈해야 하는건지 화끈하다 has a lot of meanings. It could be sexual, meaning hot, or could be an adjective describing a person with temper and determination. So this means 'Why (sb) needs to be hot/determined' You're talking about Gentleman right haha enjoy

알랑가몰라(너가 혹시 아는 지 모르겠어) 왜 네가 화끈해야 하는 건지 I don't know if you know why you need to be hot. This lyrics is kind of ambiguous.

알랑가몰라(알다가도 모르겠어) 왜 (내가) 화끈해야 하는 건지 I am not sure if I know, why do I have to be wild I hope this will help you.