I feel for Hanjoon, he's just come out of a relationship with someone who basically used him as a human comfort pillow and wasn't invested feelings-wise, granted he chose that for himself but I think he always expected Jaeha to reciprocate eventually. Now I can understand why he doesn't trust someone who is young and not exactly reliable (Jin), even though Jin seems to be earnestly pursuing him I don't see him as being genuinely invested and at this point I think Hanjoon is looking for long-term commitment.