This is Guinevere, of Arthurian Legend. She is the wife of King Arthur and Queen of Camelot. This portrait shows her at a moment of indecision. She loves Arthur, and wants to uphold her duty to him and duty to her kingdom - symbolized by her ring. When she's with Lancelot, it feels like he reaches into her soul, and as much as she tries she can't resist her love and desire for him.