My suggestion is to ditch the bersa, and get her a locked breech blowback operated gun, of which there are plenty of choices. As stated above, on your bersa thunder the only thing keeping the slide in battery when you fire is the weight of the slide and the recoil spring, so by design they HAVE to have a strong spring. A gun with a locked breech delayed blowback system is kept in battery after firing by the fit of the barrel to the slide, and the recoil spring is only used to bring the slide forward, so its normally much softer than that found in a pure blowback system.
As an added bonus, a locked breech gun has softer felt recoil, you know she wont complain about that!
ANY delayed blockback operated gun will be easier for her to rack, and many have very nice triggers. My wife has difficulty racking the slide on some guns, but is able to do my S&W bodyguard .380 easily.
Also realize that a larger, heavier gun will be easier for her to rack. Unless this is for concealed carry, I would look at a full size handgun for her.