[Fantam]

If SB is super loose, he could be calling with a smaller flush draw, a straight draw or any pair.

You could take the free card and see what the river brings, but that might encourage SB to bet the river whatever falls.

I think that I would probably bet the turn as a semi-bluff as you have a flush draw and I doubt that SB has an A. If he check-raised, then I would call and fold the river UI.

Betting might also get you a free river showdown if you dont improve.