If you know for a fact they are lying, then simply tell them. I know you are lying about whatever and I want you to stop. They don't have to of course, but you at least have told them. Just make sure you know what you think you know.
tell your friend to stop lying in a nice way. if she doesnt I would break him the news and tell him not to tell your fri end it was you
If the friend is saying mean things or lying about you, talk to the friend in person, tell him or her how hurtful this gossip is to you and ask the friend to stop.
"I feel that you are being rude to me. Can you please stop it and do not do it to me?"
Either what you know about it, or if you don't know anything you tell her that. If shes your friend you shouldn't act like you know when you don't because that's just lying.
you confront them and tell them that you know they've been lying about you and you would really like them to stop or otherwise the friendship must come to an end. hope this works =)
you tell him "why do little things mess up our friendship just be clear don't lie i want our friendship to last forever" in other words tell him or her that you know that their lying and if they don't stop and start becoming a loyal friend then you and his or her friendship will be over because the most horrible friends are he ones that lie!
you go up to her or him and ask and if you think they are lying or you can tell that they are lying to you don't trust them or don't be there friend.
Tell the truth.
You have to always tell your friend the truth and know when they are lying. It's sometimes good to fight because then you know you both care and you have to be able to tell your friend all your big or embarrassing secrets no matter what.
well if you know she is cheating on you then ask her if shes cheating on you and if she says no tell her that you know she is and break up with her. If she says yes ask her if she still wants to be with you. If no then break up with her if yes then tell her that she needs to stop seeing that other guy and promise you that she won't ever cheat on you again!!
Tell her to quit lying, and tell anyone she is lying to her actual age.
My friend commented on my beautiful knee caps and they are pretty awesome so i can tell he is not lying. He has little curls and they are cute so i'm not lying.