I put my wife through the MSF course and found her a late model Rebel 250 several years ago. She rode it for several months, but never felt fully confident riding. I then mistakenly sold that bike and bought her a Honda VLX600 thinking it would be an easy transition and maybe the "full size" bike would be more to her liking. It just never became comfortable for her, not to mention that I was becoming a danger to myself riding out front and watching her in my rear view mirrors more than the road in front of me. I subsequently sold the 600, and bought a Honda Sabre 1100 for 2-up riding and we enjoyed that for several years. She could sit right there behind me and I could focus on riding and enjoying her company instead of worrying. I've since sold the Sabre as well, but she has already commented about how much smoother the CB is than any of the other V-twins we've owned.
I don't share all this to discourage you or your wife from seeking a bike of her own, but merely to second the opinion that it's far better to keep them on something small, light and easily handled until they are the ones that say "I want something bigger."
You know I took one of these for a test ride just for giggles and I am seriously thinking this might be my wife's first bike.
2013 Honda NC700X
She is a little hesitant on the whole clutch thing as she rides a scooter now. With that bike being that it is a hybrid automatic transmission sort of like in a car, it would be a nice transition. You do have the option to paddle shift up as it automatically down shifts for you. It was fun to ride and I put over 25 miles on the test ride putting it through the paddle shifting and the full automatic. Wasn't a bad ride and they have the version with the hard saddle bags also!
Sorry if your not looking for suggestions or your wife can handle a manual transmission. Wish mine did... I have, for the time being, the spare yamaha XS-850 in the garage she could ride...
Here is the solution I decided on for my new rider bike - V Star 250. My gal is 5'3", and I wanted to make sure I got her something she could easily handle, push around, and not be in any way intimidated by. It has a 27 in. seat height, the bike weighs 320 or so lbs., and a very nice, fun, torquey power with that v-twin sound.
I can't control how she rides, or the idiots out there on the road, but I can buy new to make sure the equipment is not going to be any issue.
And if she "outgrows" it, mazel tov! I'll be happy to trade up in that eventuality.
Hmm, I tried to post a pic, and apparently too dumb to figure out how...
Ok, got it. File was to big or whatever...
I think that NC700X would be a real nice bike. I had a DN-01 and found it to be very handy. If they had priced that bike at the right point it would have done well. Crazy money for them new at the time. Lots of people ride scooters and would move up to larger machines I would think. Don't know about the seat height. The DN-01 sat low. It just needed a better motorcycle sound and a bit more HP to be a keeper.