Hi there,
I can feel the hurt and betrayal - it cuts like a knife to be exact but I wouldn't take action.
I would calmly tell my daughter how I felt.
In all likelihood the sister may have said something like come on out and we'll have a get together or party for you. Maybe the daughter had doubts and wanted to bounce them off of someone who isn't paying for or planning the wedding.
If she's going through with the wedding, she should have a home of her own afterwards. Throwing her out would just feel awful after the deed was done. You'll say you didn't mean it and that will open up an entirely different can of outcomes.
If lieing really is a newly found attribute of the duaghter you didn't know was there before, it's going to be really sticky, if the two "move in" to "save money" and over the long haul you end up having to deal with different stories or being a pawn.
Sometimes no matter how someone else feels about us, there's little we can do becasue no matter how much we love them, we'er just seen as over protective, overly sensitive, etc. they just need a 3rd party. If truly there is lieing going on, telling your daughter, again, calmly how you felt and discussing future living arrangements, not threats, but concerns about how potential indescretions could affect everyone involved, living there or not may make her more aware and less likely to hide other things that will undoubtedly happen in the future
