Get her a Taser C2. These can be really effective as I know a man who's been hit by one (Law Enforcement Officer as a "willing" test subject). He wouldn't dare talk down the unit now after it had him shaking on the floor for 30 seconds and lying there incapacitated several more minutes. $350 is stiff but that's the price of a good defense. Get her the red one; it's sexy too!
Did I mention the Laser sight and bright white LED on the front of it?