'Sure' in the Bible

He said to Abram, "Know for sure that your seed will live as foreigners in a land that is not theirs, and will serve them. They will afflict them four hundred years.

Now therefore, restore the man's wife. For he is a prophet, and he will pray for you, and you will live. If you don't restore her, know for sure that you will die, you, and all who are yours."