My new 686+ with a 3" barrel is about perfect for me in that role, and my wife can shoot it with .38s too.
You might not have to restrict her to .38s! The ladies can be surprising sometimes.
My Daughter, who is average size, knows a bit about guns and shooting but is not a huge enthusiast, asked me to take her and her boyfriend shooting, one time.
Loaded up a bunch of stuff, and off we went. Had a good day. When it came to the .357, we used my S&W Highway Patrolman (6").
Started with .38s, target was old 2x4 sticking out of a dirt bank, range about 15yds or so. First him, then her, both shot close, hit it once or twice. All shots fired off hand.
The .357s (my handloads, and NOT current "wimp" factory stuff). He shot first, results about the same. But he loved the blast and recoil. He was very enthusiastic. Daughter, not so much, but he insisted, "You have GOT to try this!"..
so, she did. Hit 6 for 6, blowing big chunks off with every shot. Boyfriend kind of deflated a bit... I suggested to him it would be a bad idea to get her really mad...
My daughter is quietly hyper capable at an amazing number of things, but making the right choice for a boyfriend right out of the gate, wasn't one of them...
My point is, don't assume your lady cannot manage a .357 until SHE tells you she doesn't care for it. Don't push, and you might be surprised.