Who is Mei-ling from A House Divided and what is their importance?

Yuan's mother discovers Mei-ling, who was abandoned in infancy, and subsequently, takes her into their home. As an adult, Mei-ling is studying to be a doctor. Yuan falls in love with Mei-Ling and repeatedly asks her to marry him. She, in turn, repeatedly refuses. Yuan later calls on Mei-Ling for help while he is in the capital ..... while his father lays tortured and dying. Mei-Ling comes to his aid, and when she sees his service to his father..... she agrees to marry him.