Take her to a range that rents pistols and have her select a few that she wants to try after looking over the selection. Or ... invite some of your friends to a range, and have them bring along their favorite pistols; then have her try those. Eventually she's find one that best fits her hand and eye, and the probem will be solved. I've long ago given up on trying to predict what a woman might want to shoot. Each is different, each has different capabilities, and all of them will surprise you somewhere along the line. One thing I can say for sure: If she is serious at all, something pink generally isn't going to cut it.
+1 on the surprise. My wife WANTS a small, light auto. I require it to be 9mm or larger. The problem, she doesn't like the snappy recoil from lighter weapons firing high pressure cartridges. +P in 9mm, uh-uh. .40, forget about it. .45? Not so sure.
But 10mm? OKAY! In fact, she is the second woman, the first was my friends 16yo >100lb. daughter, to say they preferred the G29 10mm pistol to the G17, G27, M9, 686+, on and on... The funny thing is, they don't like the 155 or 180gr. bullets at hardly any loads, but the 200gr. Hornady XTP? Loaded to 1000fps they can shoot it all day.
Go figure. But whatever you do, don't pass up the 10mm. I almost did until I saw a little girl pick it up and shoot it like it was nothing --and she was accurate too. She also ran through all my practice ammo and I had to come back and load up 200 more for myself! For some reason, it seems to be a winner. I think it is because the pistol fires a heavy enough round to not have "snappy" recoil and the pistol itself is heavy enough to mitigate it entirely.
She isn't a big fan of the size of a Smith 10mm auto, but she purse carries, and she has FINALLY come to the conclusion that Isaac Newton was right! We never made it to .45, but I think with the right fitting, a .45 would be just fine.
Come to think of it, most women I know that shoot prefer low impulse rounds. Think heavy-slow. 200gr., 1000fps. Even 9mm+P has more impulse than the heavy 10's and .45's. Anyway, I usually see them shooting .38spcl. and .45ACP. 9mm seems to be a toss up, and .40 is rare. 10mm only seems to work with the heavy bullets.
Of course there are women that fire the .500mag, but they are rare and usually wear lineman's boots.
She started with a Smith 317. They didn't make the magnum yet. It has a stiff trigger too, stiffer than I like, and stiff enough to affect accuracy DA. I changed out some springs in it, but not the hammer spring, a little polishing, and now it is a little better. She still can't hit anything with it, but she likes shooting it. She is most accurate with the M9, 10/22, and M4 (but doesn't like the M9)..
