'Assuredly' in the Bible

Go at once to King David and say to him, ‘Did you not, my lord, O king, swear to your maidservant, saying, “Solomon your son shall certainly be king after me, and he shall sit on my throne”? Why then has Adonijah become king?’

She said to him, “My lord, you swore by the Lord your God to your maidservant, saying, ‘Solomon your son shall certainly be king after me and he shall sit on my throne.’

even as I swore to you by the Lord, the God of Israel, saying, ‘Solomon your son shall certainly be king after me, and he shall sit on my throne in my place’; I will indeed do so this very day.”