You should be somewhat confident you have the best hand after the flop betting (noone re-raised you). The turn looks a bit scarey but they checked to you, so there either slow playing or dont have anything. In either case, you need to bet it and see where you stand. Any re-raise at that point probably means your beat... However, I probably would stay-in since I might pick-up a Q-high flush on the river. I would also think your opps would make a move on the turn (if they had a set, straight, or flush), but agruably they might just wait until the river (especially if they have have a high flush) before raising. Ultimately, I think you are losing money in the long run by not betting the turn in these situations.