"...and the black is sometimes white that failed."
What do you mean by "that failed"? went wrong?
In any case we need an article before this last "white" since you are placing a verb.
"and the black is sometimes a/the white that went wrong."
"Nothing is totally black or totally white, and white can often be a black that is hidding, and black can sometimes be a white that failed" this is a better way of saying the above in English that sounds as correct english...
I edited that way that is the most correct English. I'll explain why sometimes we need an article and sometimes not, before the same word.
The article is needed before a noun, but sometimes this noun is an adjective in the same sentence and in this case it does not take the article.
"Nothing is totally black (adj) or totally white (adj), and the white (noun) is sometimes black (adj) under a mask, and the black (noun) is sometimes white (adj) for it failed."
See what I mean?
I turned the end into "for it failed" (because it failed) instead of "that failed", because in the way you had done it, the line should read :
"....and the black (noun) is sometimes a/the white (noun) that failed"