In some respects, Hero is a foil for Beatrice — a character whose presence serves to show off or enhance the qualities of another character. (The term foil originated as a piece of shiny metal placed under a precious stone to heighten its luster. One of the best-known literary foils is Dr. Watson in the Sherlock Holmes stories of Sir Arthur Conan Doyle.)
Hero has her own story, of course, representing the formal courtship traditions of the period. In any arrangements about marriage throughout the play, she is generally passive. At its start, she is apparently attracted to Claudio from an earlier visit, yet she accepts Leonato's guidance to accept Don Pedro's proposal at the dance. Then she discovers that Don Pedro is pursuing her only for Claudio, and she is happy to accept Claudio. After being accused of deceit with another man, she denies any wrongdoing and faints at the shock of the denunciation. She "plays dead," then pretends to be a cousin ready to marry Claudio, and finally unmasks as a loving Hero again.
But at the end of the play Hero is probably less naive about men. She even speaks up for herself to Claudio after her unveiling: "One Hero died defiled, but I do live, / And surely as I live, I am a maid." Furthermore, she takes time to "steal" Beatrice's poem expressing love for Benedick and gives it to Benedick at a crucial moment, probably cementing the bond between Beatrice and Benedick. A changed Hero? Perhaps a first move toward self-confidence and maturity.