My wife won't ride a bike, or do anything resembling exercise.
Are there any Bicycle Clubs in your area? My club, the Fremont Freewheelers in Fremont, Ca, has Cinderella training starting in January, and culminating in a Cinderella Classic Metric Century put on by another club in our area. The idea is women riding with women, to get them interested. We do have a few men helping out, but the women apparently are more comfortable learning with other ladies. Who cares, as long as they are having a good time. Maybe getting some ladies with like minded goals together in your area would start as an occasional thing, and turn into a regular event. Let new people progress at a pace they like, and they will stay interested.