"I want a kilogram of sugar."
Translation:Voglio un chilogrammo di zucchero.
Vorrei is "I would like" not "I want". Basically the same meaning in English but the one is more hypothetical and polite, and the other is more direct. Like the difference between asking someone if they would pass the milk versus if they will pass the milk--used interchangeably in English, but actually different when you break it down.