[Guruman]

that was my thought as well. If villain has a pair and a single diamond, then the best move here is clearly to raise and punish his draw.

when he just called the flop threebet after a checkraise, it stunk of "I just wanted to see if you really hand the queen" The third diamond on the turn may have improved his hand, but not necessarily to a made flush.

If he's still drawing, we have to punish him now, before the river card. If he's got us beat, we can find a fold here as well.

This hand is not WA/WB IMO. Its narrowlead ahead most of the time and unrecoverably behind the rest.