What is the ruling on a man marrying a woman who is wealthier than him, and what is its relation to compatibility (kafa'ah) in Islam? Does this affect the happiness of marital life? And what is the ruling on a girl getting engaged to a man who is not yet able to provide financially, and is a phone relationship permissible between them during the engagement period?

The summary regarding compatibility in marriage is that the preponderant opinion among scholars is that it is compatibility in religion and character. Therefore, there is no harm in a rich woman marrying a poor man. As for a young man who is still studying proposing to a girl and delaying the marriage until after graduation, there is no harm in it, provided there are no sinful relationships during the engagement period, as the fiancée is a non-mahram and should be treated as such. As for the hadith: "Women are not married except by their guardians," its chain of narration is weak. If the girl's father rejects the proposal after all means have been exhausted, the young man and the girl are advised to sever their relationship.