A 38 revolver is fine if that is what she is comfortable with. She can load one or two shot shells if she want to get his attention without killing him.
In the news today was just such a scenario where a lady shot a perp 6 times hitting him in the face and neck 5 times with a 38. I’m surprised the guy lived but so far he is. One really lucky bad guy.
I read that. The 38 airweight is a fine weapon. One add I would give. That perp would be dead if she had a mosquito. JMHO. 22lr hollow points a given.