I was thinking about the CaptainSwanFire triangle and about love triangles in general and in every triangle involving two guys and a girl, there is always the “nice guy” and the “bad boy”. In the case of CSF, Hook is the “bad boy” and Neal is the “nice guy”.
Normally the girl goes with the “bad boy” for a while before she realises that she’d be much better off and happier with the “nice guy”. The “nice guy” always gets the girl in the end.
So CS may happen but ultimately Neal and Emma will end up back together in the end.