Is there a saying like that in English? Googling it only came up with discussions about Hell. I also tried searching this forum, with no results.
In my native Finnish, the saying goes “totuus ei pala tulessakaan” (literally "the truth doesn’t burn even in fire).
I’ve heard, “The truth will out,” meaning “The truth will always become apparent no matter how you try to cover it up.”
Unfortunately that won’t do, the burning part is sort of essential 
I’ve heard it used to indicate that if you toss something in a fire (ie subject it to a rigorous winnowing process) everything that’s NOT true will disappear.
While I can’t think of a specific saying, the concept does exist in English, especially in relation to legal matters thanks to the play “The Crucible” by Arthur Miller, about the Salem Witch trials. While there are no literal crucibles in the play, the title refers to the idea of the accusations and arguments being “boiled down” in court.
There is also an awesome line from a Star Trek episode that sums up the concept nicely. “Your honor, the courtroom is a crucible; in it, we burn away irrelevancies until we are left with a purer product: the truth, for all time.”
The english phrase “crucible of truth” carries the core of this idea. A crucible is a vessel in which items are raised to a high heat so impurities can be burned away.
Damn, semi-scooped by Jenaroph. 
It seems (to me anyway) related to this http://www.ehow.com/how_4488547_test-gold-fire.html.
Testing gold with fire is old enough to be mentioned in the Bible.
Thanks for the replies. Looks like I’m gonna have to abandon my original idea and see if I can work with crucible.
ETA: Thanks tallcoldone, I’ll check that out.
The only place I’ve ever heard that is when Della Street said it on the promos for the Perry Mason Show and although I understood what it was supposed to mean, I could never parse it grammatically.
I suspect it’s short for “the truth will [come] out [in the end].”
Like many great English phrases, it’s from Skakespeare:
Merchant of Venice, Act II, Scene 2.
According to a few Finnish books on popular sayings, this one is listed simply as a Finnish folk saying. So for your translation you’ll have to find something similar that conveys the message.
However it seems that the Aesop “Prometheus and Truth”, which tells about two statues of Truth and Falsehood being put in kiln, might have something to do with the origin of the Finnish phrase. The international sayings “lie has no feet” and “truth prevails” are also present in the same story. Perhaps you can work something out of that?
I once heard Desmond Tutu say this about apartheid
I don’t understand a lot of the nuances of 16th or so century English, but another example that Bill used was in “Julius Caesar:” I will myself into the pulpit first. . . . I see what he’s saying, but in normal conversation we would think there’s a verb missing.
And I’m sure there are lots more in his plays.
Oh, damn. Well then, looks like I need more creativity than I thought
“The truth passes through fire and does not burn” is a Nigerian proverb, if that helps…
Yes, this is awesome. Anything similar in other languages?
It has a fallacious implication to my ears. It’s sort of saying, “If honesty is brutal, then brutality is honest.”
Nothing comes to mind, Kamrusepas - but there is much I do not know…
Oh, I didn’t mean you specifically, the question was for the whole forum