The truth can be one of the hardest things for a dishonest person to give to you, but there are some methods of tricking people into giving up the truth. Although mind games might not be the way you choose to communicate with others, getting the truth out of someone can be done by following a number of different tactics.
Compose yourself in a way that will convey your own honesty and truthful intent. Proper posture, direct eye contact, approaching the person face to face, and the use of hand movements will make you appear natural and without suspicion in the liar's eyes.
Make the liar think that even if the truth were to come out, you've got some secrets of your own that would make the lie seem very minor in comparison. When the person starts to develop curiosity and inquire as to what you have done, encourage the dishonest person to come clean first.
Tell the person that you know that the suspected lie was not spoken intentionally, and shift the focus of the lie from the action of telling the lie toward the emotional reasons for telling the lie. This will make the lie less important to keep from you in the liar's eyes. Suggest that the reason for lying must have been justified.
Convince the person that she has actually done you a favour by lying. Make the person see a benefit to what he has kept from you, so that the lie does not hold as much weight as it did before.
Tell the liar that she only has a single option. This is done by suggesting that only truth will save any remains of the friendship, or that the friendship will be lost forever when the truth reveals itself by other means. Also, let them know that this is the final opportunity to come clean, before you begin going to other sources for the truth, which will also result in a loss of friendship.
Make the person believe that further consequences will come from their dishonesty. Tell the person that you now have no choice in the matter. Do not tell them what your plan of retaliation will be, or when, but just help the dishonest person develop the idea that the lie itself may not be as problematic as the consequences to follow.
Put the weight of responsibility for the lie into another person's hands, instead of the person you are trying to get the truth from. Tell the liar that you feel another person is putting pressure on the liar to continue being dishonest; this will tear away at the ego, which may be a part of what's holding back the truth.
Make the person think that the truth is of no concern to you, in order to strip the person of the power that comes from keeping it secret. This will often times lead to to the deceitful person giving up the truth, in order to reclaim some sort of importance in your eyes once again.