She needs self-confidence and methods of winning. Try Judo or Thai Boxing. That way she can defend herself to anything if necessary. Those are proper methods of winning (not those martial arts with the colors, belts and breaking blocks. those are more for show and not for defense. they work when fighting someone who knows the same fighting style.). Just try to get her self-confidence which she can get when practicing Judo or Thai Boxing. Also, she needs to understand that the thoughts of others don't matter if what they say is not true. And if it is true, then you have to deal with it. Acceptance.
It's what helped me during my time at school and still helps at work and college.