For me, the steps below really works, sabi nga nila daig ko pa daw ang NBI investigator manghuli ng nagsisinungaling... But before you talk to your subject (sus NBI talaga hahaha), make sure that you gather enough info para di ka naman mapahiya hehehe!
There are often cues and signs that someone may be lying. There may also be understandable reasons for the lie.
Look for body language that might indicate someone is lying, such as not looking you in the eye when speaking to you, being fidgety, or acting nervous or uncomfortable.
Listen for inconsistencies in what the person tells you, such as different stories on different days, different time frames, mistakes in remembering details or mixing up details.
** another tip, try to ask questions non stop then go back to your 1st question. If his/her answer is different from the 1st one... something's wrong...
Notice if the person steadfastly resists answering any questions. Extreme defensiveness could mean that he or she is trying to hide something.
Notice if the person accuses you of lying or being deceitful when you really haven't been. This could reflect the other person's own underlying behavior, which he or she is projecting onto you rather than owning up to it.
Listen to your gut and intuition. You may just know someone is lying. If you are not sure, don't jump to conclusions. Try to get some evidence to back up your hunch.
Consider asking directly if the person has lied to you. Many people feel bad getting caught up in lies, and find it a relief to finally be honest.
Try to be understanding and listen to the person's reasons for lying. Was he trying not to hurt you? Was she afraid you would be angry, upset or disappointed?
Look at your possible role in having someone lie to you. Are you someone who gets so upset hearing the truth that others feel they can't be honest with you?