gewiss

In a sentence

• Er ist gewiss ein talentierter Musiker.

  He is certainly a talented musician.

  Here, 'gewiss' functions as an adverb meaning 'certainly' or 'surely', to emphasize the certainty of the statement.

• Ich habe gewisse Zweifel an seiner Geschichte.

  I have certain doubts about his story.

  In this sentence, 'gewiss' is used as an adjective ('gewisse') meaning 'certain' or 'specific', referring to the nature of the doubts.

• Nachdem er die Prüfung bestanden hatte, war er sich seiner Sache gewiss.

  After passing the exam, he was certain of his matter.

  Here, 'gewiss' operates as an adjective meaning 'certain' or 'confident', indicating clarity or assurance in one's position.