Masterofnone, she will have to see the pain it causes.

A niece told some casual lies that led to her and a friend nearly getting killed by me in a farm accident. It would have been an accident, but still they would have died. She was 13 when it occurred and from then on she was so honest with me she rarely had anything to say around me.

I think if you can find a book about a lie leading to disaster that she can empathize with, that might be a point of discussion.