He looks into the eyes, but something is wrong... The body will never deceive, even if the words sound convincing.
Lying is not just a set of phrases. It is stress that manifests itself in small things.
You may not be an expert in psychology, but your intuition is already on alert. Pay attention to details that reveal internal discomfort.

The first signal is the eyes. If the gaze darts, avoids direct contact or, on the contrary, becomes too intent, this is an alarm bell.
A liar often blinks more often or, on the contrary, freezes, trying to control himself.
The second marker is the hands. Touching the face, rubbing the nose, covering the mouth with fingers are subconscious gestures that try to "mask" the deception.
The third sign is a change in breathing. If speech becomes intermittent, the partner takes deep breaths or breathes quickly, this is a reaction to stress.
The fourth moment is the legs. The direction of the feet towards the exit, the swinging of the toes, the fidgeting in place. The body unconsciously prepares to escape, even if the person is outwardly calm.
The fifth clue is inconsistencies in details. The liar gets confused in the details, adds unnecessary details to sound more convincing, or, on the contrary, speaks in too general terms.
The sixth signal is the voice. Unnatural pauses, changes in timbre, coughing. Some start speaking louder or quieter than usual.
The seventh clue is overprotection. If a simple question causes aggression or attempts to change the subject, this is a cause for concern. The liar feels threatened and attacks to avoid pressure.
But remember: no gesture is 100% proof. It is important to analyze behavior as a whole.
What to do if your suspicions are confirmed? Don't interrogate them. Say, "I think there's something you're not telling me. Let's discuss this honestly."
Give your partner a chance to explain, but don't ignore your feelings. Trust is a foundation, and cracks in it need to be noticed in time.