Which member of the Capulet household is not only aware of the pending marriage but is assisting with it?

Juliet's Nurse knows about the marriage. She brings Juliet the message of when and where it will be, and later brings a rope ladder so that Romeo can climb to Juliet's balcony so that the lovers can spend their first night together. Juliet's Nurse is the only other person that knows about Juliet's marriage. The nurse the person that brings the letter that Romeo sends to Juliet.