Snub nosed .327 Federal Mag. This gun can fire the extremely mild 32 S&W, the .32 S&W Long, the .32 H&R Magnum and the .327 Federal Magnum. Some people even claim it can fire the even milder .32 ACP, but I haven't tried that. Full strength .327 Fed Mag rounds produce an awesome amount of recoil and noise, but low recoil SD loads are available for it, as are SD loads in .32 H&R Magnum.
The Taurus Model 327 holds 6 rounds where most .38s hold only 5. If she can stand the longer 3" barrel, the Ruger SP101 might be better for her and Ruger may eventually produce more of these with a 2" barrel. The S&W Model 632 is another option, but $$$.