Former LEO here. As the others have said, spend some serious range time with her and let her shoot several different styles, brands and types of hand guns. She's got to be comfortable with it, or it's a waste of money. As for what I personally recommend to people (after someone here recommended it to me) is the Sig P238. The .380 has become a potent round rivalilng 9mm with the advancements they've made the past few years. The P238 is extremely easy to rack (two fingers) and just as easy to shoot. It's a 1911 style pistol so you get the great trigger that 1911's are famous for and also the quick, easy and reliable thumb safety. It's very small so people with small, and/or weak hands can handle it easily. At the same time, I find it very easy to shoot with my large hands.
I would definitely advise you to try and get/rent/borrow a P238 to let her try. And maintenance on it is a snap. I'd say even easier than a revolver. Lastly, it's a Sig! Sig Sauer makes great firearms and the P238 is no exception.