Ruger .380 or S&W .45?

[compulsion]

What for you may be the best decision for a CHL weapon is probably not going to be a great decision for your wife as a shooter...

I personally carry a Ruger SP101 .357 mag revolver. It is absolutely accurate and reliable and that means everything to me in a concealed. I can't imagine any situation where I would need to lay out multiple rounds in self defense. I like revolvers as well for women in that they seem to be more intuitive to a very casual shooter.

I'll add that I do not enjoy shooting "compact" pistols. So a revolver that I can just keep loaded and tucked away for a specific purpose is ideal. I know for sure I will never jam up even if it hasn't been touched in months.

For a weapon you will shoot regularly, and will be in the home or car(in some states) I would go with a full size for sure, but that is another topic entirely.

If you already have the 12ga at home, depending on how much your wife likes shooting, I think that should cover what she should use for defense if needed. My mom has a 20ga, and should it become necessary, I think her chances of taking someone out with the shotgun is a vastly better than her chances with any pistol.