Who is Nada from The Haj and what is their importance?

Nada is a sister of Ismael's. She is two years older than Ishmael. She becomes romantically involved with Sabri. After Sabri is sent away, Nada is sent to work in Amman, caring for the children of a United Nations official. She becomes romantically involved with her employer, his personal secretary and the fedayeen leader. On a visit to her parents, Ibrahim brings up the subject of marriage, and Nada tells him she will decide who she wants to marry and when. She also reveals that she is not a virgin. She is killed by Ibrahim because of the dishonor she has brought on her family.