How can you tell whether buyers are lying?

Negotiators have been known to lie during an important meeting. How can you tell whether buyers are lying? What should you do if you catch them telling a lie?

While making the purchasing and different dealings it is very important that the both parties tell the description with complete fairness.  If any buyer are telling lie in dealing than it can damage the deal, there are different sings and points that can represent or show that the buyers are telling lie.  It is very easy to notice that either the buyers are making true statement or not. There are various facial and formal signs that can represent the statement. It can be observe if the buyer is making in extreme formal way and trying to look good in front of the seller in very formal ways than there is something he is not telling truth Moreover the facial expressions of the buyer and his eyes can tell the true story because the person cannot maintain confidently eye contact while telling lie or his facial expression will change if he makes false statement about anything. It is very obvious here that the sales person should give some time for the customer so he can decide and should make easy deals with them. Moreover the wording of buyer after finishing presentation can represent his truth with regard to product.