as·sure 
/əˈʃuɚ/ verb
as·sures; as·sured; as·sur·ing /əˈʃuɚ/ verb [+ obj] 1 : to make (something) certain : ensure
▪ He believed that hard work would assure his success. [=that hard work would make him sure to succeed] ▪ We must assure that every child gets a proper education. = We must assure a proper education for every child. ▪ Winning the Nobel Prize will assure [=secure, guarantee] her a place in history. ◊To assure someone of doing something is to make it certain that someone will do something.
▪ A victory in this game will assure them of finishing the season with a winning record. 2 : to tell someone in a very strong and definite way that something will happen or that something is true
▪ I can assure you that you won't be disappointed. ▪ She assured me (that) she was OK when I talked to her on the phone. ▪ 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. ▪ These mistakes won't happen again, I (can) assure you.
▪ He believed that hard work would assure his success. [=that hard work would make him sure to succeed] ▪ We must assure that every child gets a proper education. = We must assure a proper education for every child. ▪ Winning the Nobel Prize will assure [=secure, guarantee] her a place in history. ◊To assure someone of doing something is to make it certain that someone will do something.
▪ A victory in this game will assure them of finishing the season with a winning record.
▪ I can assure you that you won't be disappointed. ▪ She assured me (that) she was OK when I talked to her on the phone. ▪ 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. ▪ These mistakes won't happen again, I (can) assure you.
assure yourself
: to make yourself sure or certain about something
▪ He tried opening the door to assure himself that it was locked. ▪ They managed to be third in line, assuring themselves of good seats for the concert.
▪ He tried opening the door to assure himself that it was locked. ▪ They managed to be third in line, assuring themselves of good seats for the concert.
