Not sure if this is the definitive version, but I got it from a John Denver TV show, and the simple chord arrangement has stood me in good stead for many years.

                G             D      G 
  Be sure it's true when you say I love you  
    

       G      B7     C 
  its a sin to tell a lie   
    

D                              G 
  Millions of hearts have been broken  
    

A7                             D 
  just because these words were spoken  
    

        G          D     G 
  I love you  yes I do I love you  
    

        G        B7        C  
  If you break my heart I'll die  
    

        C                     G           E 
  So be sure it's true when you say I love you  
    

       A7      D      G 
  It's a sin to tell a lie  
  

Cross my heart, hope to die
I'll never ever ever tell another white lie.
Took my little girl out on a date last night
next to her gravel gertie woulda looked alright
Now I'me between the devil and the deep blue sea
'cos I said baby you look good to me
I told he I loved her and oh how I lied
Now she's gettin set to be my blushin' bride
If she leads me to the altar I'm sunk
I cannot tell the preacher I was drunk
So Lord have mercy on a no account sinner
Give me one more chance and let another guy win her
Cross my heart and hope to die
I'll never ever evr tell (one more time)
I'll never tell another white lie.

Line Breaks <br> added. Preformat commands <pre> (beginning) and </pre> (end) added to space chords.
-Joe Offer-