That was going to be my comment. And no matter what the men say, some women will only carry in the purse. There are dedicated purses for this purpose and they are best, but the styles are limited. So for purse carry, and for inexperienced shooters, the revolver.
I have a 340PD (but no purse). The enclose hammer is best for this type of carry. I also have a 640 Pro, and the added weight makes it easier to shoot.
If she turns out to be recoil sensitive, then the Kel-Tec .22Magnum is light and carries a 30 round magazine. It will be loud, but the recoil will be very light. Ammo ain't cheap though.
S & W makes a model 351C, revolver that weighs 10 ounces and carries (I think) eight rounds of .22 magnum. Enclosed hammer. A good gun for someone who is recoil sensitive and wants to carry in a purse or pocket.
I think the Nano is going to be a bit heavy in recoil. I've not shot it though.