[signal]

IMO a bet on the turn is mandatory. If you get raised on the turn, then strongly consider folding. If she just calls, the river can be checked behind or bet for value, depending....

I think a turn bet accomplishes the following:
1. You are not giving a free card so you charge her for drawing to a flush
2. Same thing if she has king-dust; you charge her for trying to pair her kicker.
3. You keep the pressure on her and will probably score am option to have a free showdown.

I think though if you check behind on the turn, you basically have to call on the river since you often will induce a river bet from a wider range (she did donk the flop after all).

If she does not have two spades in the hole, the turn ace is actually a good card for you. It narrows her range since such holdings as [As4x] and [As3x] have been eliminated. Also, it puts an overcard to the flop that you can represent.

So basically, a turn bet/fold is my vote. A lot of the time here she has king-dust with that flop donk based on how the FW 10 game plays.

Who is this villain here? Does she wear glasses and have short, blonde hair, kinda butch? If that's her she definitely would donk the flop with a 4-flush.