You can never completely tell when someone is lying. Not even a lie detector can do that. Do you understand what that means? That means that not a single one of the tips we are about to give should ever be used to determine that someone is lying without reservation. Even if someone does all 25 of these things they still may be innocent. The power of circumstance cannot be overestimated and people have even been known to give false confessions because they were being pressured to “tell the truth”. With that said, there are certain things you can look for that might arouse your suspicions. These are 25 ways to tell if someone is lying to you. Sort of.