I seem to say this every time one of these threads pops up, but you can make hash from seeded bud, and from hermied plants. If your girlfriend is willing to smoke hash, or if you make edibles/oil with it, you'll still get a harvest, and your time and effort won't go to waste.
Bubble bags are pretty inexpensive.
For what it's worth, I've grown for years and I have never had an unintentional herm from a fem seed, and they're all I buy now. If I were you I'd try out a few other breeders. Try out a few singles.