This kiss will forever and always be my favorite kiss. Do you see how they look at one another? That was the first time Emma had ever looked at Killian with trust and love in her eyes. He has a look of relief that he had finally won her heart over and he was willing to do anything to win it.
He traded his ship, his home, his life as a pirate for her, and she opened up to him letting her walls down for the first time.