Who is Wong Kwai from Gladys Aylward: The Little Woman and what is their importance?

Wong Kwai is a Chinese woman. She traveled to Ireland as a housekeeper and nanny. Wong was wrongfully imprisoned as a lunatic because of accusations levied at her by hateful woman. Gladys visits Wong in the asylum, learns her story, and frees her. Wong Kwai becomes a happy Christian, who is always ready to tell anyone and everyone about the love of Jesus Christ.