For some US people, dinner expense=intimacy obligation

Once I talked to a Chinese girl who started middle school in US. She said that US people really enjoy intimate contact, and treat such things lightly. If a boy pays all the expense for a dinner, wine, a movie, and popcorn, somehow the girl will feel the pressure to pay him back in an intimate way. Otherwise, if the words spread out in the school, that girl will have a bad reputation, and will be shunned in the future.
I have no idea if that is true or not, or is restricted to certain area.