[soah]

checking turn makes no sense at all here. like, really bad. giving a free card to two players on this board... why?

given the action there are only a few legit hands that make sense for bb because overcalling the flop with KJ or better seems bad/unlikely. when we get to the river he could easily have a busted flush draw and you are representing basically nothing other than pocket threes. So it's certainly conceivable that he could be bluffing. Maybe not often enough to justify a call (depending on reads) but this is hardly a spot where I'd feel like I can fold here and always be right.