I would say "Truth needs protection" is the natural answer. There is no need for the 'the' in front of 'truth' unless you were talking about a specific 'truth', and there you would more likely say 'this truth' or 'that truth', not 'the truth'.
It is equally as natural to say "the truth needs/requires protection". You will find "the truth" in plenty of sentences and more often than not "sự thật" implies "the truth".
There is no need for "the" before protection. It is more natural to say "The truth needs protection".
"The truth needs the protection" doesn't make sense in English. Only one "the" is necessary. "The truth needs protection" is what it should be.
Yes. But "The truth needs the protection" is still right. And in Vietnamese, before a noun, need a definite article. I know that.
"The truth needs the protection" is very unnatural sounding. It's very forced. Maybe because you don't speak fluent English you don't know this.
I already know that. It's very unnatural sounding. But the grammar is right.