My wife loves her S&W 6906 9mm. Its a stout pistol to be sure. It's heavy, but she likes it over my AMT government as it doesn't snap up as much (due to the weight). She is now looking at getting a S&W snub nose 357. Of course right now she is wanting to get a shotgun of her own as well. My wife isn't a large gal either, she just has confidence although the 12ga's are giving her what-for.
I highly recommend letting her pick it out. You might even go with the premise of getting yourself one and see what she likes.
My wife has her own tastes in firearms, and as of two years ago she hadn't even so much as fired one. While she still likes her clothes, jewelry and entertainment she also likes making her own decisions in regards to what she carries. I know how it fits her hand makes a HUGE difference. For example, she likes the S&W 357, but didn't care for the Judge, purely based on how it fit her hand.
She also liked the Bersa Thunder 380, and Walther PPS. The makarov's aren't terrible, but some places you may have trouble finding ammo. One of the nice things about 9mm... its everywhere and comes in a zillion flavors.
Oh, and stay away from pink guns unless she specifically says she likes them. It was like the lionel lesson. Years ago they made a pink trainset for girls... only to discover that girls who wanted trains... wanted trains that looked like trains, not the Easter express (of course now those pink trains are very valuable due to the scarcity). Every store we go into, someone wants to show her a pink gun. I have yet to see her so much as glance at a pink gun.