There are a growing number of options out there these days. A lot of it will be just you and your wife going to a store and getting it in your hands and more importantly letting her try out a few. I have found that getting a holster for a woman is actually much harder due to the vastly varying size and shape of their hips. Being able to try one on is really critical. Belly band style holsters are quite popular these days as most women are wearing yoga pants or some variation thereof. The belly band style keeps the gun very secure and flat to the body without the need for a gun belt. I also recommend that women appendix carry if possible because of the fact they tend to wear tighter fitting clothing and having a weapon on their side will make it print very clearly.
That being said I cannot specifically recommend a specific holster or brand but I can tell you two things to specifically stay away from.
1. DO NOT use the holsters that attach to the bra (Flashbang). They are a good concept if you have all the distance in the world to draw the gun. However in a struggle reaching up into your shirt to draw a firearm is a great way to get your arms pinned by the perp or get your gun snagged in the material. Also useless if she has a dress on.
2. Make sure that its an on body holster. Too many women carry in their purse. First thing to get snagged by the perp? Purse. Snatch and grab is the primary method these days. Then boom, she is unarmed and has just suppled bad guy with a Glock 43x for his next victim. No bueno.