[Ginogino]

Acesover8s:
It's not completely clear from your post, but it appears that it's UTG that you're against on the river. At the river, your concern is that you're up against a flush (or possibly a broadway straight).

UTG's pre-flop and flop betting pretty much eliminates the chance that he holds a small diamond. If he held the Queen or Ten of diamonds, he might check the turn hoping for a check-raise, but if he had done this and you'd checked behind, he'd pretty much have to lead bet the river for fear that he'd lose another big bet by checking again.

His betting pattern pre-flop and on the flop makes it very unlikely that he holds QT for the straight, so I'd figure that your set of Kings was good, and I'd bet the river.

Gino