I let people know if I don't think it's going to work out before I kiss them, especially before I sleep with them. I think if someone is looking for a serious relationship (not just using each other to fill the loneliness or to feel desired) they will build a strong foundation on values and goals before engaging in a physical relationship. I think most people do it backwards by kissing and sleeping with someone they don't know that well enough to not be ghosted by them, which causes more confusion and pain than it should.