Verb: It means to state confidently that something is true or will happen, or to remove doubt or fear.
*Example: "I can assure you that the project will be completed on time."*
Adjective: It is less common but still exists, meaning free from doubt or worry.
*Example: "He had an assure manner, which put everyone at ease."*
The part of speech will depend on how it is used in a sentence.