What is the solution for someone who feels incomplete and unmarried, despite possessing all good qualities, and whose situation is not improving?

Everything that befalls a servant is by Allah's decree and destiny, and Allah wrote it fifty thousand years before He created the heavens and the earth. Allah Almighty said: "No disaster strikes upon the earth or among yourselves except that it is in a register before We bring it into being—indeed that, for Allah, is easy—in order that you not grieve over what has eluded you and not exult over what He has given you. And Allah does not like every self-deluded exultant." The believer is content with Allah's decree. If good befalls him, he gives thanks, and if adversity befalls him, he endures patiently, and that is good for him.

The girl should entrust the matter of her marriage to Allah and not cling to causes such as beauty, knowledge, or lineage. Rather, she should know that Allah alone is the one who marries her off if He wills. She may strive to the best of her ability, such as offering herself to a righteous man, or having her guardian offer her to someone he believes to be upright, as 'Umar, may Allah be pleased with him, did with his daughter Hafsah. She can also ask trustworthy people to search for a righteous husband for her.