Reference: Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa. – Volume 18, Page 30, Fatwa No.4921, Question 5
Question: Is it permissible for a young woman to abstain from getting married [again] after the death of her husband?
Response: The Sharee’ah strongly encourages marriage, so it is upon the guardian of this young woman to advise her to get married and encourage her in this. However, if she refuses [to do so] and does not fear any fitnah for herself, then she can abstain from marriage and that is her affair.