It's a matter of context
That sugar is sweet : that particular sugar is sweet
Sugar is sweet: generally, sugar is sweet. Any sugar
For both context, the translation would be: Gula itu manis.
So, maybe you want to keep in mind, that the word "itu" is not used only to describe something out of reach, but also to point out general truth.
Bumi itu bulat (Earth is round)
Garam itu asin (Salt is salty)
Olahraga itu baik untuk kesehatan (Exercising is good for health)