How should I tell her?

I have this friend that has really bad hygiene. To the point where my mom doesn’t even want her coming over cause she would leave a smell. I really want to tell her but I don’t know how. She’ll take it the wrong way and get offensive especially with something like this. It’s not only her body odor but her breath as well, and she’s always in my face But I don’t want to be rude and move away. How should I tell her ???