The best thing which you can do for your daughter is to send her to a martial arts school where she will gain confidence and the ability to protect herself when needed. We have found a real story which shows how an woman which was simply closing the restaurant got harassed after she allowed a male to use the restaurant bathroom.
In the pictures it is viewable how the male started to attack the female, but he did not expect the female to be a trained martial artist. The female directly hit the male when he tried to attack her, the male did not leave it at the first attack and he followed her to the street.
The female was forced to strike the male attacker on the street and she was very successful in it. She gave him some good kicks and punches and then she fled the scene. A couple of weeks later the male was arrested and it was only possible because the female was able to protect herself.