'Certainty' in the Bible

know for a certainty that Jehovah your God will no more drive these nations from out of your sight; but they shall be a snare and a trap unto you, and a scourge in your sides, and thorns in your eyes, until ye perish from off this good land which Jehovah your God hath given you.

See therefore, and take knowledge of all the lurking-places where he hideth himself, and come ye again to me of a certainty, and I will go with you: and it shall come to pass, if he be in the land, that I will search him out among all the thousands of Judah.

David therefore sent out spies, and understood that Saul was come of a certainty.

To make thee know the certainty of the words of truth, That thou mayest carry back words of truth to them that send thee?

The king answered and said, I know of a certainty that ye would gain time, because ye see the thing is gone from me.