This being a romance movie, it's hard not to have a couple of contenders
Julia Roberts traveling on a 14 hour flight just to see her son for 2 hours before she has to leave again (she's a soldier on active-duty)
Edgar and Estelle's reunion in the cemetery
Holden returning from a 14 hour flight, finding Sean waiting for him.
Sean: You heard?
Holden: I heard.
Cue the sweetest, most emotional look ever.
Kara's Anti-Valentine's Day party- as cynical as it may have sounded, the whole thing is rather sweet in that her friends and colleagues can come when romance has gone sour and just have fun with people they do care care about. And it works. When they party is wrapping up, everyone is having a good time, and some of the guest from the wedding party had joined them.