'Certainly' in the Bible

Then Abimelech called Isaac and said, “See here, Rebekah is in fact your wife! How did you [dare to] say to me, ‘She is my sister’?” And Isaac said to him, “Because I thought I might be killed because of her [desirability].”

They said, “We see clearly that the Lord has been with you; so we said, ‘There should now be an oath between us [with a curse for the one who breaks it], that is, between you and us, and let us make a covenant (binding agreement, solemn promise) with you,

When Jacob came in from the field in the evening, Leah went out to meet him and said, “You must sleep with me [tonight], for I have in fact hired you with my son’s mandrakes.” So he slept with her that night.

Send one of you [back home], and let him bring your brother [here], while [the rest of] you remain confined, so that your words may be tested, [to see] whether there is any truth in you [and your story]; or else, by the life of Pharaoh, certainly you are spies.”

Joseph spoke harshly to them, “What is this thing that you have done? Do you not realize that such a man as I can indeed practice divination and foretell [everything you do without outside knowledge of it]?”