how can you understand if someone lies?

how can you understand if someone lies?

eyes always tell the truth

For me, if the person that already around with me for long time, I can track them if they tell me the lie or truth. Some people they can show the face that he or she lies something. But some of them cannot because they are too expert about it. If my young brother tell me a lie, I can track him from his lips and eyes. But for other person I dont know. Just follow the story flows. 

Eyes never Lies

Nowadays, almost all people become very good actors. They can lie indefenetly without any difficulties, even some poeple have pleasure to see you believing them and take it as a great victory.

I'll tell him not to lie next time.

It's my more experience and next time will not believe anyone easy.

there must be some reasons for his lying I am sure

and fogiving is decided by them in my opinion

In my experience and I am nearly 50,  all things lied about have an untruth feel about them the slightly unbelievable. To good to be true is an english saying !

if my good friend lies me , since maybe i don't belive anybody.

It takes a lot to understand why people lie. But I know that sometimes people have to for a few reasons. In my opinion, however, a lie can only give you a temporary relief. It will not get you off the hook. You will eventually find yourself up against a wall and your lie catching up with you. So as difficult as it may seem sometimes, it's better to just stick to the truth.