I think a foundational thing is that becoming a JW is like getting married forever. How would anyone make such a big step without being very careful? And since there are so many rumors that JWs is a cult (she might have heard them), wouldn't it be a wise--and Biblical--thing to TEST ALL THINGS first? Talking with former members and researching JWs online to be sure that you can agree with everything she finds is a wise thing to do, right? (And isn't wisdom and discerning commended by God?) Tell her that she might have heard a warning that anyone who opposes the JWs is getting worked on by Satan, which is also used by other cults to discourage her from investigating. If God was pleased with the Bereans who looked at ALL the info they could find, before making a very important decision, then she can trust God to clarify the Truth thru cross-examination:
Psalm 18:17: The first to present his case seems right, until another comes forward and questions him.
So, help get her in the frame of mind that is OK with research, and the rest can be more of a downhill ride.
I'd ask her what things she has heard, what areas she has questions about, and start there. Your personal story--and the experiences of those you know--will be great illustrations of the real policies and teachings.
bebu