My wife has small hands.
Small hands make it look bigger lol. She has a walther p22 and it could be a little bigger. I was thinking maybe a taurus 24/7 g2 in 9mm. Small grip frame and a good small caliber.
I have short fingers and can handle just about anything fairly well. Full size double-stack Glocks are about the only thing I have a problem with; and the problem is my normal full contact on the trigger. I get a good enough one for shooting at the range, but not a good enough one to feel comfortable carrying one as an EDC. On the other hand, I have ZERO problems with a 1911. And there is such a thing as too small. I'm so not in love with my Taurus 85 BUG anymore; I despise pinky hang.
Chances are any single stack firearm will be fine.
However, there's no substitute for having her try a bunch on for size. There's a whole lot more to comfort than whether or not her fingers can wrap around the grip.