I like Delilah, although I think it could be hard to deal with the biblical connotation, depending on where you live. Like it would probably be fine in a largely secular place, but if you live in the bible belt, it might be a drawback.
I don't personally like the name Gwendolyn because I don't like -lyn(n) names, but it's not awful, and I think it goes fine with Delilah.