If there is a safety concern, buy her a trial lesson.
Actually, don't buy her a trial lesson. Buy her a three-pack of "pilots wife" lessons or whatever you want to call it. For a change, the instructor sits in the LHS, your wife in the RHS and the instructor teacher her what to do when you become incapacitated. Things like tuning 121.5, following vectors and making a safe landing in not-too-challenging conditions.
Throw in a few other easy-to-handle emergencies and if this gives her an idea, at the very least, that she's competent to do something in case of an actual emergency, she'll be a lot happier.