'Certainly' in the Bible

They replied to Joshua, "Because your servants had been informed that the LORD your God had certainly commanded his servant Moses to give you the entire land and to destroy all of the inhabitants of the land before you. So we were terrified for our lives because of you. That's why we did this.

Moses made a promise to me on that day when he said, "The land that you covered on foot will certainly be your inheritance. It will belong to your descendants forever, because you have fully followed the LORD my God.'