Nobody can ever " make" somebody else comfortable in the water. I suggest she work with an instructor while you stay away.
I had an issue with mask clearing and I'm not sure when or how it developed. I didn't have it when I was first trained. I believe it was because I didn't practice it in my first 50 dives and became afraid to clear my mask or take it off underwater for some reason. It eventually became a big issue that I really had to work on, especially in colder water. I spent a lot of hours in my pool taking my mask on/off on/off. Breathing off the snorkel without a mask, removing my mask and swimming across the pool while breathing off my regulator. I still do these drills regularly because I know this is was an issue for me.
Mask clearing and losing one's mask are absolutely essential skills. You can and probably will experience mask flooding and possibly a loss of mask while diving. If this causes panic, it could turn into a life-threatening event, when it should really be a non-event.
I carry an extra mask in my drysuit pocket. 2 weeks ago, in a single lobster dive to 90 feet in cold water,I had a mask kicked off ( and recovered), mask flooded, and a free-flow regulator because I had a bit of sand in my regulator from an earlier beach dive.
All of these were non-events because of training and experience. I frequently practice skills in my pool, taking my mask on and off, switching from my primary to secondary regulator, etc.
I believe your wife needs a lot of time with an instructor or at least a really good, experienced mentor, who can spend many hours in the pool going over skills again until they are boring, then out to the open water to do it all again and again and again. During this time, perhaps you can find a mentor to work with you? Two new divers, one just below the level of panic, are not a good match.
in addition, I suggest that you both take some extra courses, Advanced Open Water, Peak Performance Bouyancy and Rescue Diver, as soon as possible.
If you are both near a UTD or GUE instructor, you might look into their recreational level courses because they go more in-depth into skills and should go a long way towards increasing your wife's confidence. The recreational level courses for both GUE and UTD may provide the quality of instructor you are searching for, since you state that you're having trouble finding a good instructor. Both of these agencies have very rigorous Instructor quality control.