Rule #1 - let HER pick.
Rule #2 - do not infringe upon, or attempt to influence, Rule #1.
Rule #3 - have her take a training course, from an objective, non-personally-involved, person.
I learned rule 3 when I was selling motorcycles for years. Guys teaching their gals to ride? Great way to guarantee a divorce. No joke. You DO NOT tell her how to do...ANYTHING. If YOU teach her, any criticism will be taken as a personal attack - constructive, or not. If a 'stranger' teaches her, it becomes objective instruction. Trust me. I've seen it in action.
She needs to be comfortable with whatever she's going to carry. If she isn't comfortable wearing, carrying, handling, cleaning, and shooting it...she will lose interest and it will sit on a shelf. If the comfort level is there...she'll be dragging YOU to the range!
Let her try various guns. If you go to a range, I can pretty much guarantee other folks there will let her try a few rounds if you explain the situation. If you're in Maryland, she can run as many rounds as she wants through my XDs.
Do not tell. ASK. Don't try to steer her opinion, simply ask "how do you like that?" How does it feel. How does it make HER feel. What does she NOT like about it? Asking questions makes her analyze it, which will in turn help her pay attention to each and every round she puts through each and every weapon, and ultimately help her make her decision. Ask her the questions about details she needs to pay attention to. Do NOT give her those answers...just help her learn the right questions to ask, so she can make the right decision for herself.
HER decision.
If she asks...answer honestly. But don't voluntarily try to tell her anything - just ASK. Guide her to her own answer.
I'm going through a similar situation with a close friend. She hates guns. Terrified. Her 18 year old daughter shoots (quite well, actually). Her ex husband shoots. I shoot, and I carry daily. When I started carrying, I was very explicit with her about it and we went over the "if something happens to me and I'm incapacitated, here's how you handle/clear/safe my weapon without hurting yourself or anyone else". I found out months later that my gun scared her, and she hated me wearing it.
Last week, I found out she took a range class. We were working on a house I'm selling, she walks up to me, and says "hey, show me your grip when you shoot your gun". I was dumbfounded, and through that exercise I learned about the class, about the grip she was told to use (basically the "B" grip from the "does your grip make you miss" thread), and about how her ex, her daughter, and I, all use the same grip as each other, but it's not a "B" grip. And, she wants to try our grip, now that she understands some more reasoning behind it (which basically validated what she was thinking anyway).
Different reason for her to start shooting, to be sure, but she took it with ZERO influence (or knowledge) on my part. She took it for HER reasons, and she took it so she could stop being afraid of the machine that I wear on my hip every day.
Turns out, she actually likes shooting, and the photo I got of her first target (full-frame Glock rental) was pretty damned good. Not sure if she'll actually buy a gun, or start to carry one (that's a hurdle-from-hell here in the Republik of Maryland, but she has the advantage of being a single mom and having an employer who'll sign off on it as well)...but she has interest. For HER reasons, not mine.
