There are many methods of discernment of truth and falsehood. The main of them is based on the observation of facial expressions and gestures. If you learn how to read them correctly in the source, you find out he's lying to you or not. But if he has the concentration and self-control, it is unlikely that you will succeed. If only you won't be as attentive and focused.
In any case, remember that the liar is always harder than you in the sense that he feels some discomfort, as it feels that there is likelihood of its exposure. If he fully controls his gestures, that is not easy, but doable, then surely in the speech to make mistakes it will be easier with the help of your guiding questions.
So, the person who tries to deceive you, in every way trying to divert your attention from the essence of the conversation, diluting your speech useless facts to be more persuasive and, as it seems, to submit to our attention more plausible picture.
When your opponent frequently uses the words in conversation from your question, it indicates that he is with you not honest. Even if he takes the serious conversation into a joke, you know, he's trying to lie to you. Also, the rate of speech you can discern that he is lying to you. If it with frequent tempo changes and intonations, pauses, then the person is insincere.
The manifestation of turbulent emotions usually indicates that your opponent is trying to cover up their true motives and to divert your attention. Follow look. If the person in the conversation often looks away to the side, he is lying to you. I hope these observations will help you to bring clarity in dealing with people you suspect of insincerity with you.