You're HU in the pot.
You're on the turn.
The board shows a 4 flush. You have the nut flush.
Generally in this spot, if I pot pot, I could come reasonably close to taking their stack, but usually not all of it. Unfortunately, getting them to call a pot sized turn bet and river bet, even with my image, is pretty tough.
I've been trying several different lines in this spot and I am still not sure what the best way to extract the most with this hand is.