Informal, chiefly North American; used as an intensifier meaning 'certainly' or 'very'.
Translations
He sure looks happy today.
Сегодня он действительно выглядит счастливым.
Definitions
Certainly; without doubt; definitely (used to emphasize the truth of a statement). He sure looks happy today.
To a great extent; very (used as an intensifier before adjectives or adverbs). It sure was cold last night.