[X] Move in and hug her. She can't hurt you anyway. That's just a regular knife, after all. And when you've got her in a hug, reassure her and let her know that everything will be alright. (Empathy + Speech Check)
[X] Disarm and restrain her. You can figure out the rest later. Right now, you need to take that weapon away from her. Then you can talk. (Karate Check)