You don't need a lie detector to tell if someone is telling the truth.  The answer is all in their body language.  Daniel Goleman, author of... Emotional Intelligence, says: "The rule of thumb used in communication research is that 90 percent or more of an emotional message is non-verbal." Meaning, if you pay attention to someone's body language, you'll should able to tell if they are being honest with you.

Here, according to Goleman,  are some things to look for to read body language to tell if they're lying:

-They scratch their nose when talking.

- They look upward and rightward while talking.

- They can't look you straight in the eye.

- They fidget a lot while talking.

- They are vague and lack details in their story.

- They hesitate before answering any of your questions, instead of just plain ol' knowing the answer. 

- They are constantly telling you "I'm going to tell you the truth here … Or asking, "Can I be honest with you?"

- They change breathing habits. When nervous, a person might breathe harder, clear their throat, or sigh loudly.

- They have their fingers crossed behind their back. (You caught me.  I'm lying about this one)