The first thing to keep in mind when you happen to be a girl's confident (being a boy who is willing to have some emotional/physical bind to her), is to assume that the lady in fact has already done many stupid things, portraying herself as an unworthy prospect for someone like you who has carefully kept away from possible regret-generating situations throughout life.
So expect her to have been dumb, stubborn, and naive. Furthermore, expect her to keep being like that for a while, even after you've already told her the reasons not to behave on emotional vulnerable ways; to avoid shame, pain or hurt. Even after raising in her an apparent consciousness about the ways to keep emotionally stable. Should you have done this, whenever she makes a mistake (again) you will not know frustration feelings, and will be able to keep that kind treat with her; providing calm, warm polite words that can aid in her emotional recovery and never hurt her with the sharp edge of the raw truth. Just like when we have to deal with them when they «just» say: "Sorry, I like you like a friend better".