A dear person whom you trust lies to you and gets caught. What do you feel? Feel cheated, sad, angry, disappointed, compassionate, disillusioned, wonder, shock, embarrassment, loss of respect? Recently when someone lied to me, I felt happy and more love, for he was not a good liar.
Had he been a good liar, he would not have been caught. He was so innocent that he could not even lie properly. If he had not been caught, how would you know he was a liar? So you see, you can never know a good liar.
The person you call a liar is not a good liar, she or he is innocent. So when someone lies to you, there is no need to go through all the above listed mental gymnastics. Instead, just melt and dissolve in love.