Just tell that you left the WTS. more on your initiative rather than listening or reading apostate information.
Tell her you don't read anything much about the JWS, that you left out a lack of believability and that your fine
with her still being a devoted believer.
.
All you can do from this point, if your really want to keep a line of communication with her.
Express yourself not as an opposer but accepting of her own personal beliefs.
Be kind and open .
All the best.