What are the signs in a conversation to determine whether a person is lying to you or not?
There are many ways to distinguish between lies and truth. The main ones are based on the observation of facial expressions and gestures. If you learn to read them correctly in the interlocutor, you can find out if he is lying to you or not. But if he has concentration and self-control, then you are unlikely to succeed. Unless you are just as attentive and concentrated.
In any case, remember that a liar is always harder than you, in the sense that he feels a certain discomfort, as he feels that there is a possibility of his exposure. If he completely controls his gestures, which is not very simple, but feasible, then it will be easier for him to make mistakes in speech using your leading questions.
So, the person who is trying to deceive you is trying in every possible way to divert your attention from the essence of the conversation, diluting your speech with useless facts in order to be more convincing and, as it seems to him, to present to our attention a more believable picture.
When your opponent often uses the words from your question in a conversation, this indicates that he is not honest with you. Even if he translates a serious conversation as a joke, you know, he is trying to lie to you. Also, by the pace of speech, you can distinguish that he is lying to you. If speech with a frequent change of pace and intonation, pauses, then a person is insincere.
The manifestation of violent emotions usually indicates that your opponent is trying to cover up his true motives and divert your attention. Watch your gaze. If a person often looks away when talking, then he is lying to you. I hope these observations help you clarify your interactions with people whom you suspect of insincerity with you.