Take her to the range and get her into guns.
+1 but my experience as a range officer is that husbands teaching their wife is a sketchy proposition at best. If possible get her into a class for ladies.
Seriously, Take her to the range and get her trained by a professional.
My wife was very scared of guns until I bought her one and took her to a range. Now, she is OK. Wouldn’t want me to carry about, but the sight on one in the house only brings up: “Why is that out?” “Are we going to the range?”