A tip up barrel Beretta will work but those come in .22, .25. and .32, assuming there are any around at all. Any .22 caliber revolver will work, the S&W 43c is a good, modern choice if a .22 will work:

Model 43 C | Smith & Wesson

They tend to have hard triggers but can probably be modified some.

But if you must stay above .380 you're not going to find a host of revolvers that will work except J-frames in .38 caliber (.38/.357 but you'll stick to .38). A lightweight J-frame is an excellent purse gun but (i) she needs to be prepared for some vicious recoil, and (ii) she needs to properly carry it where it is easily accessible, does not get messed up by other things in her purse, and (iii) she never loses contact with that purse.