Ladies bike? First, does she want to ride and not just to satisfy the male partner? Second, is she timid or aggressive? Third, is she athletic?
My wife took up riding to experience what her male partner and 3 male offspring did when we camped, so I picked up a AT-1 Yamaha - electric start, 125 cc heavy pig for her first bike. This was in the early seventies, she could climb most anything that we would take her on but had to talk her down most inclines. Most of the time ended with her upset! Case in point, have someone other than the husband teach them!! After two or three years I picked up a Honda TL125 for her, big improvement and a real confidence builder. She quit riding in the late 70's when we moved to the West side of Montana; mainly because the boys where in so many sports we did not have time to camp and ride as a family.
We got back into camping after the boys were off to college, this was with a group younger than us just starting their families. The same thing happened to these families as when we started and the wives (and kids) started to ride. Remembering what we went through I made myself available to help the ladies on our family rides to keep tears at a minimum. The first two ladies to take up the sport became good riders and progressed through various bikes, sadly neither of them ride any longer. Then even younger couples joined the group. Two of the gals without kids now ride with the guys at the guys pace for the most part, one started out on a Honda 230 and progressed to a KTM 200 and is now on a KTM 300 - the other young lady started on a KTM 250 4 stroke, moved to a KTM 350 and is now on a Husky 300; both ladies can keep up with the guys.
The point is that there is no one bike that is a ladies bike and the more we guys realize that exposing them to different rides will help in their enjoying this great sport. I would really like to see Beta USA bring in the 250 XT, but any bike that is easy to ride will help them build their confidence and allow them to progress.
Whew, what a rambling post - but I hope I made my point.