The pot was about 12$. It was limped around and I limped with 23s.
I flopped on A45 the nuts.

A guy who plays tight and is not a donator, was complaining how he is getting sucked out on every flop with over pairs because higher cards hits the board, happened about 7 times in 3 hours(KK,QQ).
He leaded the flop for 20. I thought he is strong because he leads the pot. I decided not to raise to provoke another bet. I call, and an Asian who calls pretty much anything with a pair calls.

Turn is the 7 , board: A457, flush draw possible.
The guy who leaded flops checks. I tank a little bit and think he is strong and bet ?? into the pot of 78$.

That answers your question. He's tight, he overbet and got two callers. He was probably going to fold unless it was checked through or he paired his kicker. Sometimes you don't get paid on your strong hands.

It sounds like you can make an immediate profit against this villain by floating the flop with ATC and then betting if checked to. If that is true, then this is the downside of that, but it is vastly outweighed by the upside if you take advantage of it.

Is checking on the turn an option ? Flush draw out and a lot of rivers can kill the action because it's then an 4card straight board.

OP, please don't post results. I'd take them out, but I couldn't keep from making it obvious that V folds turn.

Your sizing is fine, and never checking turn. Some players overbet weak TPs and give up if called, others are betting big for fat value. It's just unfortunate that you ran in to one of the first type of overbettors.

Raise flop. He's never putting you on 23.

Turn is a must bet, can't consider checking with the FD now out there. 1/2 - 2/3PSB looks good to me.

No, don't check. Bet and hope he's got a hand to come along with you.

Playing 23 PF is almost always bad from any position except the BB. When he overbets the flop I would expect him to be pretty strong here (a good Ace at minimum), and would probably just raise now. As played, turn is a must bet. Sizing depends on stack sizes. Bet an amount that lets you shove the river for around 1/2 pot.

That's half the story.

The other half is that people fold a lot more turns than rivers. On the river when he calls he gets to see your hand. On the turn when he calls, he has to potentially face another bet on the river.

Whether lots of rivers kill action or not is debatable. Does he think you bluff every flush draw that comes in? Maybe he calls when scare cards come?

All that said I think betting 25 on the turn is best. That's around 1/2 pot. As LifeRebooted said, if he folds to that sizing after over-betting the flop you've found a way to print money against him.

If your turn bet makes it obvious that you're planning on shoving the river, the Villain is folding a large percentage of the time. We should NOT be trying to fold out all hands worse than 68.