Villain (12k)
Hero (10K)

Blinds 100/200

Hero raises to 600 in MP+2 with AsAd
Folds to the Villain (BB) who calls

Flop
JsJc9s
Villain checks
Hero bets 800
Villain calls

Turn
8s
Villain bets 1500
Hero calls

River
Kd
Villain bets 2700
Hero ??

Is villain 85 year old man, 40 year old woman, or 19 year old kid with hoodie on? Any previous hands you've seen V play?

Villain is a 50 year old man who has been playing a lot of hands. Running pretty hot too

Running hot is not necessarily relevant... but i choose to infer he is playing ABC and he is betting when he has it. The board sucks for one overpair against his perceived range and his two street donk. Sigh fold. The only thing you are beating is KQ that he donked with a turned gutter. Seems unlikely he donks turn with a gutter, no? More likely is a jack that donked when the straight card peeled on the turn.... or q10...sets... 89.. lots of his BB flat combos are ahead of your AA, especially since he donked the river when the K rolled off. It didn't slow him down.

Has he shown down anything that would lead you to believe you can possibly be good? What are you ever ahead of?

I think you see a hand like QJ very often here.

would say you're beat 8/10 times here

pot on the river is 5900 and he bets 2700 making it 2700 to win 8600 ~3.2-1
only value hand we can beat i think is k9s but he still might just check call river (or maybe kqs donk turn w/ gutshot and flush draw. We need to win ~31% to break even in this spot so we need to think villain is bluffing 1/3 times here with the added times of betting a rivered k to make a call right. Sounds like old man prob wouldn't bluff that often in this spot so unless some sort of live tell made me think bluffing was more likely, i sigh and fold. calling not terrible though since you still have 5600 left if you are wrong which is 23bb as opposed to 41bb with a fold and 84bb if you call and win.

against an old man this looks like the snappest fold in the world otr