Jamie Sullivan is a complex character who defies stereotyping. When she is first described, she seems unattractive, yet it is her attractiveness that surprises Landon several times throughout the novel. She carries a Bible with her everywhere, but later the reader realizes that it is not a symbol of her piousness but of her connection to the mother she never met.
In many popular novels, devout Christians tend to be devout on the surface but then judge others for their non-Christian behaviors. Jamie, however, does none of this: Although Jamie does not consume alcohol herself, she does not chastise or distance herself from Angela when Angela does. Instead, Jamie sees that Angela is in need and provides assistance.
Likewise, Jamie does not try to teach Landon any life lessons, but she continues to believe there's a good person hidden inside him in spite of his behavior to the contrary. Jamie's belief in Landon troubles him enough to cause tremendous change in his personality and value system. She asks the tough questions, she holds him accountable, and she holds him to a higher standard than he has ever been held before, but she does not judge, scold, or manipulate Landon in any way.
In spite of having a much-older father and no mother, Jamie has a close-knit, loving home life. In spite of not having any brothers and sisters of her own, she shares her life with orphans who are close to her own age. In spite of not having much money of her own, she shares her time and money with others at every opportunity.
Jamie is dying, yet she and her father tell no one so as to avoid the pity that often accompanies such news. Instead, she spends the last year of her life helping others experience the best times they've ever shared with her. She is one of the best students in the class, yet she will not attend college and hopes only to have a large, happy wedding before she dies. She has great faith but admits that it is shaken from time to time, as she awaits death.
Truly, Jamie Sullivan is a study in contrasts.