advice on how to kick someone out of your house (nicely)?

[Rb10chris]

Hey all, so last year my wife's sister invited herself into our house after some arguing with her parents, we thought she was only going to stay a few days/weeks, ended up being almost a year now. There have been times where she tells us she's looking for a better paying job, taking interviews, and also looking for her own place (but she can barely afford it at the moment). She doesn't pay rent, doesn't help out around the house, just pretty much goes out to smoke, and then hides in her room all day.

Out of courtesy to my wife, I haven't straight up kicked her out yet, but I have told her that if she plans to stay any longer I'm going to charge her rent. Also telling her that moving back in with her parents is an option, but nothing we say can make anything happen. I feel like letting her stay here for free has enabled her to be lazy and not take action and make her own life better. What advice can you guys on here offer me in this situation?