Show her some pictures of what you like and then some pictures of a hariy pussy.
I keep a little triangle patch but the lips gotta be clean shaven for my own comfort and satisfaction.
When she does finally shave herself good, go down on her like you never have before. Lick and touch her smooth outer lips, tease her with your tongue, don't rush it, let her enjoy the new sensations she will only be able to feel without the hair there.
Baby oil works great for shaving the pussy. She can sit at the edge of the tub on a washcloth so she can see what she's doing. There are websites that will go into detail about shaving a woman, do a search on google and print it out for her. Wrap up the article in a little basket with a washcloth, new Venus razor, baby oil, a candle and a bottle of wine. She may get a little irritation when she first starts shaving, but if she keeps it up, it will go away. I shave every day and it only takes a minute since it's kept up daily. The longer she waits inbetween shaving, the longer it will take.