I think the Ruger would be a great solution …
If she doesn’t like the Ruger however; a compact 1911 in 9mm has very little recoil and carries well. I like Para’s, but Kimber, Colt, and Springfield, come to mind as manufacturers of compact 1911’s in 9mm. Unfortunately I think they are all over $500 new.
If she really is recoil sensitive … Taurus makes a nice little .22 mag, 8 shot revolver. It’s loud, but it works, is under $500, and doesn’t kick at all.