That Jenny uses body language reading to detect when someone is lying.
Explanation:
Body languages involves every movement that the person does, even the slightest move or tick counts as it. Most people have a singular characteristic movement when they tell a lie.
Some blink, other touch some part of their body constantly like the hands), some others look to a certain point, etc.
Jenny is most likely to use this as a method for detecting other´s peoples lies, which is very effective once you know look very close to the person and its signs.
