My wife has a beretta model 84 in .380 that she finds very soft shooting, and shoots very well. For a woman, my wife has medium hands, I tried to get her a Beretta Cougar 8000, but she went back to the 84. Taurus made a version of the model 84 also, and if your g/f has REALLY small hands, there is the model 85, a single stack in .380. That's the lightest caliber I'd reccomend for a defensive pistol, and it's a pretty nice little piece.
If you go for revolvers, my wife was really fond of her 4" Ruger Service Six in .357 magnum, loaded with 38spl +P. The wooden grip those came with was very slim/small, and easy for most women and small handed shooters to grip. Recoil on that piece also seemed to "roll" up a little, instead of shove back. She shot that one well, but preferred the autoloader. She didn't like my S&W revolvers, Taurus model 85 4", Taurus 92, Glocks, or my 1911.
Just find a range with a LOT of rentals, or invite some friends shooting and let her try a few other guns on for size. When my wife was interested in shooting, I took 9 guns to the range, and let her shoot all of them. Took 4 nights to clean them all, but she found one she liked.