to assure = to make someone sure "i assure you, it is correct" (same as "you can be sure it's correct") to be assured = to be made (to be) sure, eg. if someone assures you, someone makes you sure.

Ian's is the best answer. I just want to add that to be "sure" is to be certain of something. It can also be used in the place of "yes" in some situations. Ex: Will you take out the trash? Sure.

example:i am sure i will win example: i assure you its the best machine it is assured.

Rest assured that I am not sure.