certainly know that # 01_GEN_43_07 # And they said, The man asked us straitly of our state, and of our kindred, saying, [Is] your father yet alive? have ye [another] brother? and we told him according to the tenor of these words: could we certainly know that he would say, Bring your brother down? 
certainly know that # 24_JER_13_12 # Therefore thou shalt speak unto them this word; Thus saith the LORD God of Israel, Every bottle shall be filled with wine: and they shall say unto thee, Do we not certainly know that every bottle shall be filled with wine? 
certainly know that # 24_JER_40_14 # And said unto him, Dost thou certainly know that Baalis the king of the Ammonites hath sent Ishmael the son of Nethaniah to slay thee? But Gedaliah the son of Ahikam believed them not.