J. R. R. T. on liars

Tevildo however, himself a great and skilled liar, was so deeply versed in the lies and subtleties of all the beasts and creatures that he seldom knew whether to believe what was said to him or not, and was wont to disbelieve all things save those he wished to believe true, and so was he often deceived by the more honest.

— J. R. R. Tolkien, ‘The Tale of Tinuviel’ (c. 1917)