I'll add another vote for the 20ga BPS if you think she'd like a pump gun. Great shotguns. If you get a smoothbore barrel you can use rifled slugs out to 100 yards and they will make deer very dead, very fast. My dad used his 20ga 870 Wingmaster with the cheap Remington Slugger rifles slugs and killed a remarkable number of deer with it party hunting during the Iowa shotgun season, and with just a vent rib and bead no less. I don't recommend this for your wife, as my was an outstanding instinctive shooter (uncanny might be a better word) before his vision went downhill and he switched to a scoped muzzleloader. For her I'd suggest rifle sights, a 1 to 4x shotgun scope, or even a red dot reflex sight mounted to the receiver. If she just wants a slug gun, you might also consider going with a New England Firearms rifled single shot 20ga and sabot slugs. Good little guns at a very reasonable price, and they're ready for optics. It is only a single shot, but if she's using sabot slugs and a scope, and has the patience to wait for a good shot, one is all she should need.

Good luck.

Mike