Did you even understand Jesus' claim, ". . . Every one that is of the truth heareth my voice. . . ."?
Yes, I did.
I'll list the passage that I believe that you are referring to:
"Pilate therefore said unto him, Art thou a king then? Jesus answered, Thou sayest that I am a king. To this end was I born, and for this cause came I into the world, that I should bear witness unto the truth. Every one that is of the truth heareth my voice." ( John 18:37 ).
The way I see this stating, Jesus is telling Pilate that He was sent to bear witness of "the truth"...
Himself ( John 5:31, John 8:14 ).
Pilate asks Him in the very next verse,
" Pilate saith unto him, What is truth?" ( John 18:38 )
The Lord does not reply, because, to me, He already has said what He wanted to say for the benefit of the reader ( John 20:30-31 ), His sheep, knowing that it would be inspired of the Holy Ghost for John to write down.
I see the Lord speaking, once again, spiritually ( please see John 6:63 ), not carnally...
Not according to the "natural" man's understanding, but according to the "spiritual" man's.
The born-again reader of His spiritual words.
Purposefully
not giving Pilate answers that he would understand, is fully within His right to answer or not to answer, as He is God and is beholden to no man's examining of Him... or us even asking, "what doest thou?" ( Romans 9:19-20, Daniel 4:35 ).
In addition, I see the Lord "being evasive" and speaking spiritual things in the parables to others...
Why?
Because they are "without".
" And he said unto them, Unto you it is given to know the mystery of the kingdom of God: but unto them that are without, all [these] things are done in parables:" ( Mark 4:11 )
To them that are "without" ( outside the body of Christ ), all things are done in parables to conceal the truth from them.
Pontius Pilate was, "without".
Christ then chose to speak to him in this way.
Why?
Again, because it is God's prerogative to hide or reveal Himself to whosoever He wishes ( Matthew 11:27, Luke 10:22 ), to be gracious and merciful to whomsoever He wishes ( Exodus 33:19, Romans 9:14-16 ).
Having established that, I see this:
He is telling Pilate that everyone who is "of God"/ "of the truth" ( "of Christ", of His body ), "hears" His voice...and they do ( John 10:27 ).
That is why I made the connection with John 8:47.
"He that is of God heareth God’s words: ye therefore hear [them] not, because ye are not of God."
God's blessings to you.