high pair on the flop

[StrictlyStrategy]

I raise A5o otb sb folds bb calls. BB is new but he looks like he's from europe so he's probably the worst ever at best.

Flop comes 254r because I hate fish and the dealer knows that. Hecheckraises me and I 3bet because I can beat a few hands. Turn 4 he checks I bet he calls because he sucks.

River bricks off a 2[img]/images/graemlins/heart.gif[/img] which honestly is probably one of the 40 best cards I could have seen so whenhe checks to me I have to bet right? What if he raises?