Good Morning b.deb,
pat701 is right on target. I'm convinced that the P239 is among the world's best personal protection handguns. It's 100% reliable. A self-defense handgun that is not 100% reliable is not a self-defense handgun. For clarity, no mechanical device is 100&% reliable. The idea is to get as close to 100% reliable as possible. The P239 is such a handgun. Its weight mitigates recoil thereby allowing one to keep its muzzle pointed at a threat. Recoil should never take a muzzle off a threat.
I'm a bigger caliber and heavy bullet is better dude. Others see it differently. Hence, I'd recommend a .40 S&W. But it the end, it'll be preference.