promiser

Example:The company gave a pledge to all employees that they would be well paid for their hard work.

Definition:A formal and sometimes legally binding promise, especially to give or to do something

Example:She was a committer to the idea of regular meetings every week.

Definition:A person who has made a commitment or a promise to do something

Example:He offered to be a guarantor for the loan to make sure it would be repaid.

Definition:A person who makes a commitment to guarantee or ensure something