His boss 'assured' him that he had her continued support. = His boss 'assured' him of her continued support. = “You have my continued support,” his boss 'assured' him.
You can 'rest assured' [=you can be sure] that these mistakes won't happen again. = 'Rest assured', these mistakes won't happen again.
They are not 'assured of' being paid. [=it is not certain that they will be paid]
(..) She succumbed in a matter of seconds. Now ... Are you sure you want to play this game? I'm afraid you'd lose. Rest assured... If you attempt to bring destruction down upon me... I shall do the same to you. My respect for you, Mr. Holmes, Is the only reason your still alive. (..)2011 Sherlock Holmes: A Game of Shadows
(..) He's expecting it. Tell him our friend thinks I delivered it to his sister. Ah... Stay While I check the contents. I was assured full payment would be there. Yes, But assured by whom? Have you ever met him in person? Hold it, Hold it, Hold it...Don't move it. Judging by the size and weight (..)2011 Sherlock Holmes: A Game of Shadows