Sadly, considering the magnitude of Emmet's crush, their life is gonna suck for a bit if Sam's not interested.  I remember being about that close and inseparable with someone, and how hard it hit when she told me that she started going out with $now_husband.  Even five years older and used to such rejections,, that gutted me for a bit.  Still, in the end, things worked out.  They're happy, it turns out that she and I would have been totally incompatible anyway, and with him I gained an additional friend.