Generally, I think OP is on the right track: 4" K-frame .38 SPL. Great combo of size, power, controllability, ease of use, and availability of ammo.
However, I strongly agree with the advice to get one that fits her hands! My wife is a decent shot, but has small hands and can't manage a K-frame or Ruger Service-Six well at all. Totally different story with J-frame, Colt D-frame, or SP101.
Since she hasn't shot much, stick with wadcutters if you choose a .38. +P will likely intimidate her & make her afraid of the gun. Along those lines, STAY AWAY from lightweights/airweights. Felt recoil may ruin her for shooting. Ditto for shotguns with buckshot--a great combo for most who are posting here, but generally lousy for women who shoot very little, don't like guns, small/weak/old, etc.
Strongly consider a good used .32 S&W Long in J frame if she is small/weak/afraid of guns. Far less kick & report than even mild .38s, but .32 wadcutters are far more effective than .22s. Also, as someone pointed out, trigger pull on .22s is typically far harder.
Also, based on your description, autos are out, as are semi-auto, pump & lever rifles. Yes, guys, I have owned and like all of them, but I've also seen how my wife & daughters wind up confused on safeties, unloading tubular magazines, safely unloading cocked weapons, etc. If they train repetitively on one gun, they get pretty good, but introducing them to various guns over the years has simply confused them. They're NOT "dumb," they just aren't into shooting as a hobby (despite my efforts
and shoot rarely. Nonetheless, they can put a hand-sized group on a 5-7 yd target with centerfire handguns that fit their hands.
Good luck, and kudos for helping her out.