Hero is presented as a very young, beautiful, innocent, virtuous, modest, and naive maiden. In fact, she is really the only truly consistently virtuous character in the play, making her the true "hero" of the story, since a hero is a person of superior, noble, and virtuous character. As the play progresses, Hero is shockingly slandered, which transforms her into a woman who is more familiar with the ways of the world, however, consistent with her virtuous character, she is willing to forgive.
One thing we see that proves Hero's modest and virtuous nature is that when asked by the other characters to help join in the plot to trick Beatrice and Benedick into falling in love, like a modest maiden, she replies, "I will do any modest office, my lord, to help my cousin to a good husband" (II.i.329-330). We also see her modesty presented when, on the morning of her wedding day, Margaret shocks and embarrasses her with a sexual joke. For unknown reasons, Hero confesses to feeling blue, or heavyhearted, as we see in her line, "God give me joy to wear it! for my heart is exceeding heavy" (III.iv.22-24). Margaret makes a sexual insinuation by replying, "'Twill be heavier soon by the weight of a man" (24). Feeling shocked and embarrassed, Hero chastises her servant, saying, "Fie upon thee! art not ashamed?" (25). The fact that Hero feels embarrassed by this true sexual reference shows us that she is indeed a very modest maiden but also that she is very naive.
After she is wrongly accused and slandered by both Claudio and Don Pedro, she agrees with Friar Francis's idea to proclaim her death, allowing Claudio time to repent his accusations and feel remorseful, making her seem more lovely to him than she did when she was his, as we see in the friar's lines:
And every lovely organ of her life
Shall come apparelled in more precious habit,
More moving, delicate, and full of life,
Into the eye and prospect of his soul
Than when she lived indeed. (IV.i.235-239)
Not only does faking her death make Claudio feel remorseful, it allows time for the truth about Don John's treachery to be known. Furthermore, it allows time for Hero to fully forgive Claudio and agree to holding a second wedding.
Hero's horrible experience with treachery and slander helped her to grow up into a woman who is less naive and more familiar with the ways of the world. It also helped to solidify her caring, virtuous, and forgiving nature.