Is a person's marriage dependent solely on God's will, or is it necessary to exert all efforts—including those that are extremely difficult—to achieve it?

Marriage is among God's decreed destinies, and belief in divine decree does not mean abandoning legitimate means. One should employ means such as supplication (du'a) and having a good opinion of God. There is no blame on a woman for offering herself in marriage to a righteous man, provided it adheres to Islamic guidelines. God's decrees unfold with wisdom and mercy. God may divert something a servant desires to store for him something better, due to the servant's ignorance of his own best interests.