If there's any way you can get your wife to try shooting firearms, she will likely allay her fear and realize the potential for good that having such an ability and availability might allow.

I've worked with a number of very intimidated people, gradually introducing them to the shooting sports by starting small and taking small steps in well controlled environments under full supervision and with constant encouragement. In most cases, after they shot their first magazine full of 22s through a pistol, their confidence exceeds their apprehension, and they are at least converted, if not hooked, that shooting can be a safe and enjoyable endeavor. It takes time, patience, and a decent arsenal, but once they take that first step, the success rate is pretty high for repeat business. The most important thing is to have an instructor that is proficient with firearms, but also knows how to work with people who have an aversion.

It's no different than with folks who don't know how to drive. They can be intimidated by that much power under their control, until they get trained and become familiar with how it feels and what to expect.