My dad tried to teach me to play golf and I thought it was silly hitting a ball and walking after it.  Tennis was much faster and more exciting.  I didn't get into golf until a good friend (and a good instructor) showed me how much fun it could be.  Emphasize the "fun"  and the competition will come later - especially if she is a good tennis player.  If you can get her and her best friend (or 3 of her good friends) and have them take a series of lessons from a good PGA instructor, I think you might get her to change her mind. 

It worked for me :)

Cathi is right on!  I would also try the "couples" approach.  Get two or three couples out there practicing and playing. 

Patience and you know what they say, "its that one good shot a day that keeps you coming back for more."

The couples approach is a great way to go.  It certainly got my Fiance more into the game.  Before she realized she had friends that played I would just focus on fun.  We never kept score, I would just congratulate her on good shots, and make sure she had a good time during the round and at the 19th. I would always take her out on Space Shuttle Launch conditions, we would only play 9, and I would make sure she's comfortable the whole round.  However, she really got into once we brought out another couple.

Now we'll play a couple of times a month, she getting pretty good, and she'll even suggest going, even just the two of us (which is what I was hoping for all along)

This is a great thread.  I've had the same dilema myself.

Couples golf seems to really do the trip. I am luckly that my wife is an avid golfer, but some of my friends wives have tried it and didn't really enjoy it.

We have a 9 hole couples event every Friday night. Some of the guys started to bring the wifes out and even if the golf wasn't that great, the social after was a lot of fun for them. Most of them have now started to play more with the rest of the ladies (along with the men on Fridays!) and are really starting to enjoy the game.

One key point....Do NOT try to teach you wife to play golf! Pay someone else to do it. She will listen to the PGA Pro and not fight with you. Trust me, I am a PGA Pro and I pay someone else to teach my wife when she needs a real lesson!

I agree with Rick.  Even though both my husband and I are PGA,  it is still hard for me to listen to him when he is trying to adjust my swing.  I pay a PGA instructor and he may say the same thing, but it just seems to makes more sense hearing it from someone else.  Go figure  :)