Just find the things what they motivates them to live .. For example, Cosmetics, Dress, Food, and also Pets sometimes. And tell her that its much easier to earn rather than working in companies. Because bitcoin is such a broad place. She can even earn just sitting infront of a PC. Give her some of your earnings sometimes to motivate her to start earning .. Give her evidences on what you have done in several days with bitcoin. Tell her your plans about earning bitcoins.
Cosmetics and Dress seems like the best reason to use though. We can tell her that you can buy that things by earning bitcoin online, i'm sure she will use bitcoin.