The vast importance of connections in most societies. Your parents, your siblings, your cousins -- first, second, third, seventh, once, twice, thrice removed -- your godparents, your foster family, your in-laws. . . all are vital, and what's more, unproblematically so. The term "nepotism" comes from the medieval era not because the practice started there but because that's where it first began to be seen as a problem.
But it's difficult to convey a world in which a young man, seeking to marry, found nothing personally wrong with one potential bride, but she was an orphan. Given that he was fatherless, he did not want to go without a father-in-law and mother-in-law as well -- too much of a burden.
Part of this is story terms. Connections are, of course, assets for your character. Giving your character assets is unwise. Well, too many assets, to be sure. Enough to keep the story going is one thing. Charles Perrault can witly conclude Cinderella with the moral.
Without doubt it is a great advantage to have intelligence, courage, good breeding, and common sense. These, and similar talents come only from heaven, and it is good to have them. However, even these may fail to bring you success, without the blessing of a godfather or a godmother.
Having your character cut off on every side for the want of connections, on the other hand, certainly does provide conflict but makes the society look a lot wickeder to modern eyes than it would have to any contemporaries. And unless the character makes connections, it's hard to see him winning a way to a happy ending.