If "in the purse" means jostling around with the rest of the junk, a revolver does seem best since the trigger pull is often so much heavier. If one is willing to maintain just one compartment in a normal purse, then a semi with a safety would be good. If one is willing to carry using a special purse with a compartment, then a semi without an external safety would be fine.
This is making me think an LCR for my wife might be best. She certainly doesn't like to train often. I also don't think having an external safety is all that safe for someone who doesn't train a lot. In a critical situation point and squeeze seems best for survival.
I suppose a steel snubbie could be good, too.
.45acp, .40 S&W, 9mm, .38 Spl, .380 acp, 22lr
12 gauge, .223/5.56x45mm, 30-30 Winchester
2 Chron. 7:14 Christians must seek His face