Please lookup: jwfacts.com. read as thoroughly as you can,,it has JW literature quotes all throughout.. Sort out some main points disturbing to you: like perhaps their shunning, blood transfusion policy, 2-witness rule regarding their internal pedophiles, college discouragement for their youth,etc.
Now the tester: go over these with her. See how she reacts. If she is defensive or angry toward your points, you will see if she denies or belittles your source (which quotes their own literature).
Then, run! If she stays wanting to know more, then have her read that site and more suggested books listed here.