Would you fold a set here?

3bet pre. I'm not sure donking makes sense on the flop either. As played, his river sizing does make this more callable than if he had jammed. It's hard to know if he would still be betting an overpair this hard or not though.

No way. Villian could have a thick value hand worse than yours or some bluffs.

To me this is one where it really comes down to counting combos of value, over value and bluffs in villains range. Im working on my hand reading so bare with me!

Value: How many combos of hands does he have that beat you? So QJ, 67 and 1010 beat you…he has 38 combos of that if I am not mistaken. He has all of those combos as a btn caller pre (maybe not 1010)

Over value: comprises lower set and 2 pair holdings. So 9-8, 10-9, and 88. He could also have A10 of diamonds though he likely 3bets that pre. Based on his raise he could also have K10 of diamonds, a bunch of Q10 and all the J10 where he thinks the 10 is still good on the river. Let’s say 46 combos.

Bluffs: I would suspect that only Ax diamonds hands with an over pair draw or a straight draw are going to make the flop raise. AK-A10 of diamonds are likely 3betting on btn and he can’t have A8 of diamonds. So we have only A7 and A6 of diamonds as a missed nut flush draw that raises flop and bluffs river. Other than that none 3bet hands he might make this play with are 56 and 67 of diamonds. All other flush draws I would suspect would just flat the flop. So that is like 4 outright bluff hands.

So by my count it is 38:50 combos that beat you vs you beat. Now let’s say he is not betting 1/2 of his 10x holdings on the river we can take 1/2 of his Q10 and J10 combos away. So let’s say it gets closer to even 38:38, but with the pot odds you only need to win 30% but only need to bright 1/2 of the time to call the river bet. For that reason I’m likely calling here.

The question is why did you flat 99 on the SB? That seems to me the start of your troubles. Had you 3bet you might have taken down the pot pre, and at the very least you restrict ranges making it easier to understand what is going on.

11 combos beat 99, I don't think QJo or 67o get called and TT is 3 combos. Thinking they bet AT or worse IP is wild for any reg. If they're a fish (likely with the flop minclick) you have to throw your flop/turn assumptions out and realize they could really have anything.

Sizing and our hand strength make me want to call.

Maybe not 67o but you don’t think btn would call QJo pre here? I’ve seen much worse than that called even from out of position. Similarly I have seen guys raise flop, and bet turn/river with nothing but top pair on these sorts of wet boards where many of the draws brickout, especially after opponent checks river. That’s why I cut down possible combos of 10x. Over values are high in low stakes from my experience.

But ya, I sort of over complicated it because I’m working on thinking things through, but I’m the end the % of hands that beat him vs pot odds dictates a call.

No fold, V couldn’t have improved on turn/river. If he flopped better, gg.