Maybe you can do some recon for her by going in the LBS and chatting with one of the employees about the situation. See if he/she is someone that you think will treat your wife with respect and patience, and then make an appt to bring your wife in later.
I was scared to walk in the LBS because I thought they would only sell "fancy" bikes to "athletes", and I just wanted an around town kinda bike. I finally bit the bullet and went in one and got so lucky to meet someone who answered all of my questions and made me feel very comfortable.
Can she try riding yuor bike before going in just to get her confidence up? Or maybe you could rent a bike for a weekend for her?