I didn't play this hand but the choice, while seemingly straight-forward, is not an easy one.

$0.50/$1.00 cash game on UB - very tight game...dealt KK in LP...I start the hand with right at $100... (EP player has him covered)

EP player raised to $3.50...folded to me - I raise to $10...everyone else folds - EP raiser calls...

Flop is QJT with two hearts...neither of my Ks is a heart...

EP raiser checks - I bet $20...EP raiser goes all-in...he has me covered...

Fold or call...

this seems like a pretty easy fold to me. Only hand you have dominated in KQ which is unlikely becuase you have 2 K's and AQ which he may play this way but its not worth the risk. If he has J10, Q10, QJ, QQ, JJ, 10 10, AK. Even if he is making this move with a draw of Ax he has his outs.

You think villain raised to $3.50 in EP with JT, QT, QJ? I would eliminate those as a possibility.

You should definitely fold--this is a really shitty flop for you. One can probably make a good argument for not betting the flop at all, as weak as that may sound.

Dig deeper... the actual answer surprised me and that's why I posted it.

What range do you put the villian on?

I put him on AK, QQ, or JJ

He either hit his set, or floped the nut straight. Maybe he even has AK of hearts and floped his gut shot straight flush

Opponent could also have a pair with the flush draw - like AQ.

I think this is an easy fold, there is almost nothing legit that you can be ahead of other than AQ. It is a remote possibilty that this player raised suited connectors and is on a flush draw, but almost anything else you are way behind. AK has you drawing to 3 cards to split, other than than you are likely drawing to 10 outs for your set or str8.

$3.50 preflop bet is not very big with a $1.00 BB. Is he someone who gives tells with his bet size? The smaller bet could well be AQ, AJ, AT, 99, 88, 77. 99 might well go all-in on the open-ended straight draw semibluff here.

Obviously Tokenizer called, and he says it's a weird hand, so I am going to guess 99.