Distinguish between the little "white" lie or embellishment and the compulsive lie. A white lie would be telling your friend her outfit is fine because she is excited about it, which unless she looks hideous, is not hurting anyone. A compulsive liar will tell you a detailed story about how they gave a presentation at work where everyone stood and applauded, only for you to find out later this person never even gave the presentation but was part of the audience instead.
Question stories. Ask for more details on any story which seems suspect to you during the flow of conversation. Listen for automatic defensiveness when you ask him for more details on a story you suspect to be untrue.
Watch her. A person's body language and reactions will tell you a lot. Fidgeting, not looking you in the eye (down and to the right) or hesitating before answering a question (giving them time to come up with something) are good signals of a lie. Also, listen for inconsistencies in what she is currently telling you and what he has previously told you or what you know from others.
Trust your instincts. If you feel that there is something off about a person and what he's telling you, go with your gut, even if the responses given to you seem completely logical.
Catch her. Ask those who were around when something you were told occurred what really happened and point it out. Tell her you don't believe her and ask her to get help. See how she reacts.
Break it off. If you have determined the person you are dating is a compulsive liar, get out of the relationship. Yes, it is a difficult thing to do with someone you care about, but you must put yourself first and do what is best. Constantly wondering what is true and what is a lie is too much stress and is no way to live your life.
Be vigilant with future dates. Compulsive liars tend to give elaborate responses to a question which can be answered simply or make a story lengthy which could be told in much less time. Liars do this by mixing a combination of the truth with a lie so it seems more believable. Listen for these things as well as watching for the body language queues so you don't get pulled into dating another compulsive liar.
- A person telling a compulsive lie believes to some extent what they say is true. It might be hard to know one when you meet one because this is so natural to them what they tell you sounds convincing.
- Liars, no matter how much practice or how pathological, will eventually get tripped up in their own inconsistencies on things such as employment, past relationships or financial status. Keep listening for small details which seem inconsistent and raise red flags.