If you want to buy a gun for your significant other - step one is to go to the range with them and let them shoot a lot of different guns until they find the one that they like.
I made the classic mistake buying the first gun for my wife. I bought her a short barrelled lightweight .38 revolver. I listened to gun shop employees who told me that it was mechanically simple, easy to use, blah, blah, blah. It's a nice gun, a S&W AirWeight, but it's no gun for a newbie. Because of the short barrel it's LOUD. Because of the lightweight, (which makes it easy to carry), it recoils significantly. That gun lives in a microvault in our bedroom as a backup.
Then I tried convincing her that my Glocks were perfect for her. Bought her a G42, (.380). Yeah, no. That ended up being mine until I sold it after buying a G43 (9mm).
Then we went to the range with a couple of friends and she shot a BUNCH of guns. She now owns (2) Sig P238's, a Sig P232, (2) Sig P320's, a Sig Mosquito, and an ambi AR I built for her using CMMG lower and Larue upper. And she sort of "owns" what used to be MY Kimber Target-II - I added ambi safety and changed the sights for her.
There are a TON of good guns on the market, both new and used. Think of them like cars, once you decide what class vehicle/gun, (truck/sedan/SUV; carbine/shotgun/pistol/revolver), you want, then you go model shopping. Test drive until you find the one you want/like, then price shop.