Lost Etymology

On my twitter account, today's quote of the day reads as follows:

"Truth can be decieving" --John Loeffler

Meaning, "this doesn't necessarily imply what you think it does." Except that that can't possibly be the source.

Since there's at least two John Loefflers, let me clarify I'm talking about the CEO of Rave Music. (The other John Loeffler is a radio broadcaster for Information Radio Network, but unless he has the answer to my question, he's not relevant to this post.) Rave Music is best known today for producing the music for the English version of the Pokémon anime.

The quote is a line from the song Double Trouble, which John Loeffler personally oversaw production for, but –despite being a songwriter himself– apparently didn't write. I credit him as the source of the quote because the songwriter (or writers) is/are unknown, and producers get credit for having had the idea.

The full lyric says, "we'll have you believing / truth can be deceiving", and is a reference to the line from the Team Rocket motto that says,: "To denounce the evils of truth and love / To extend our reach to the stars above". (Team Rocket are the recurring antagonists in the Pokémon anime, and they always try to recite their motto to the protagonists when they first meet them in an episode –and I say "try" because they're often comically interrupted, but that's besides the point).

Obviously, since the English version of the Pokémon anime appeared in 1999, it is impossible for it to be source of the quote. However, after checking every single Google result for "Truth can be deceiving" (in quotation marks) it seems like is is the oldest occurrence of the quote that there is! All the other results are people using it as blog post titles and similar. And I know the quote has to be older than that.

How can I be so sure? For starters, the Spanish version of the quote is

"La verdad engaña" --Guillen de Castro

Guillen de Castro was a Spanish playwright from the late 16^th, early 17^th century –four hundred years before Pokémon! Do you honestly expect me to believe English speakers didn't pick this up throughout the entire Enlightment Age, Industrial Revolution, and the whole so-called "Atomic" age? Especially considering that English wasn't the de-facto language of commerce until the mid 20^th century?

Of course, the form of the quote is slightly different. La verdad engaña translates simply to Truth deceives. It is a line from the play Los Mal-Casados de Valencia (The Bad Marriages in Valencia) which reads,

Original: Sería una cosa extraña. Tú no sabes que en efeto, Engaña como discreto, Quien con la verdad engaña.

Translation: It would be strange thing[s]. Thou not knowst that[,] effe[c]tively, Doth deceive discretely, He who[,] with truth[,] deceives.

(or, in non-Shakespearian English, "Strange? As you may not know, if someone can use facts to trick you, no one will realize he's tricking you!")

However, inputting "Truth deceives" into Google only returns people using it in blog posts and similar. But if this is not the original form of the quote, what is?

Nice going, Internet. You've used and abused an English phrase so much, that its source now lies lost to oblivion.