Is it okay to tell a guy this?

If a guy is trying to flirt with you and offering you drinks and dates, even though you've told him that your church does not permit dating but courtship, is it okay to tell him that you think he's trying to lure you into an unholy sexual relationship so that he can use you and dump you...and tell everyone at school what a slut you are? and that you're not going to fall for his garbage because guys like him belong in the dumpster? He's said he may marry you someday but you think that's just an empty promise as a means to get you in bed.