Depends on what exactly she wants the gun for. Is she planning on carrying it concealed? If so, on or off body carry? Is this to be only a "house" gun or primarily a range gun (target shooting)?
If she's going to carry it, then a S&W 60 (external hammer) or 640 (internal concealed hammer) is what I'd recommend.
If she's going to carry but is willing to conceal a bigger gun, then I would go with the S&W 65LS (Ladysmith) with a 3 inch tube. This will work very well for a gun kept for home defense.
If she's getting into target shooting, then the S&W 66, 19, or 686 are excellent guns that are equipped with adjustable sights. Older S&W 67s and 15s are .38 spl only, but can be readily found in good shape. Both have adj. sights. In my experience, the blued (10, 13, 14, 15, 19, & 586) models seem to have the best out of the box triggers. All of these models except the 10 are out of production, however they are relatively easy to find used.
A consideration is that the smaller J-frame guns may have heavier trigger pulls than the larger K- & L- frame guns. With any of these frame sizes, it is possible to reduce or smooth out the trigger pull quite a bit and still leave the gun reliable, but make sure the 'smith knows his way around S&Ws. Simply cutting springs is the worst way to go.