What determines truth? What determines a liar from a truth teller? If there is a brown bench and someone strongly believes that it is blue, is it true, for that person, that it is blue. How do we know that murder is wrong? And if there are a few people who don't think murder is wrong, who are we (the people who believe murder is wrong) to impose our beliefs upon them?
This is what the world is coming to without Jesus. A world without truth. So what is truth? According to Princeton University, truth is "conformity to reality or actuality."
Know we know what truth is, truth is what is real. Someone who is insane has lost touch with reality, and does not know what truth is. So how do we determine what reality is? Truth comes from a Prime Reality, Prime Reality is the thing from which everything else comes. That is what determines truth. A world with no set standard of truth, where virtually anything can be true, would be a world of chaos, a world without Jesus.
God (Jesus) sets the standard of truth. God told us not to murder, not to steal. God set the standard, He determines reality. A world without Jesus, would be a world of confused, hurt, evil people. Evil only because they believe they are not.
Another reason Jesus is truth, is the Bible. The Bible is the most reliable historical document of all time, 100% true. In John 1:1 it says, "In the beginning was the Word, and the Word was with God, and the Word was God." Jesus (who is also God) is the word! Making him truthful because the Word of God is infallible and inherent.
For these reasons "Truth" is my favorite way to describe Jesus.