“What men have called friendship is merely association, respect for each other’s interests, and exchange of good offices, in fact nothing more than a business arrangements from which self-love is always out to draw some profit.”
“Rare though true love may be, true friendship is rarer still.”
Looks like the good prince never had a friend in his long life. He sounds skeptical and bitter. Certainly there are so-called friends where the mutual interests and profit-making is the only motivation. I would rather call it a business association. In contrast, a real friendship means to be there in good and bad times, unconditional support of each other and typically lasts for a lifetime. True, it might be rare, but it is even more valuable. My two cents.