Just make sure she can handle the weapon!
My wife wanted a small .380 so I picked up a Taurus TCP .380 for her. It is small, little and carries 7 rounds total. The perfect gun right?
Wrong! Small .380's have a bit of a kick to them. The recoil, for her, was worse than my P95!
I will admit the gun barks like a bigger dog. It's not the gun you go and run a couple hundred rounds through at the range!
I, on the other hand, friggin love it! It just disappears in a pocket and loaded with Critical Defense, I trust it to do the job.
My point is, let your wife do the picking by SHOOTING the weapon first, if you can. I could have purchased a good .38 instead of the TCP had she been able to fire one before buying one!