>i told her that you would meet one of my friends at xxxx
who is a girl she assumes too much.
この場合、I told herのherと、you wouldのyouは同じ人物になりません。
もし、彼女に「君はxxするよ」と伝えたならば、
I told her that she would meet....
または、
I told her, ''you will meet..."
とならないとおかしいです。