NL16 6Max, AJo on BB vs unknown SB

I think it is a good fold. I don't see villain check calling two streets to bluff the flush in the end.
The only realistic hand he may play that weird and we beat is KQ or TQ for failed draws, but I don't think it's likely.
Maybe JQ of hearts, but then he is turning his hand into a bluff as he should just check call the river.

Our hand is just a bluff catcher and I don't think villain would bluff here frequently enough for us to call.

Flop you could bet higher as there are draws out there by the way.

Iso bigger preflop.
I think flop can go either way, big or small.
Turn ok.
River I'm calling, but that's me and my wallet. No having hearts helps too.

A fish very rarely does this call/call/donkpot line without improving to the nuts on the river. This river is also the worst card imagineable for you,all fd-s and straightdraws got there on the river. I think this is a good explotative fold. You will win a lot from this player when he has an Ax and you can valeubet 3 streets.

Btw I agree with the guys above me. Bet bigger on the flop, you have a nut hand which needs protection and value extraction. Many hands he can call with on this flop, and most likely he will call you down with any Ax on a brick board.