What is the ruling on a girl continuing to fast for a lifetime (Sawm ad-Dahr) in fulfillment of her vow to abstain from marriage to anyone other than a person she loved and made a covenant with Allah to that effect, especially since this person is on his deathbed?

The Sharia does not approve of love relationships between young men and women. Marriage is the ideal solution for those in love. If marriage is not possible, both parties should disengage from attachment, seek marriage, and occupy their time with beneficial activities. A girl's promise to someone to refuse marriage to others is not binding on her. She must accept a man of good religion and character if he proposes to her, especially if refusing marriage exposes her to what is unlawful (haram). As for vowing to fast for life, if it was merely an intention without utterance, then nothing is binding. But if it was uttered, then it is a vow that must be fulfilled. If she is unable to do so, she must offer an expiation for breaking an oath.