What is the difference between 'betul' and 'benar'?
Don't know, because they are both given as options here.
Benar = Right
Betul = Correct
Would "Ini bukan betul, ini salah" be wrong?
'betul' is an adjective and is negated with 'tidak'.
More info here :
Negation: Tidak, bukan, jangan, belum, Tips & Notes, Addendum.
And still there are sentences like darah kami bukan merah and dia bukan dari Bali here on Duolingo. How are those different than this example? Thanks.
merah is not an adjective here, it's an adverb. So negated with bukan. Same as dari Bali, it's a noun, so negated with bukan. I'm struggling with this too!