Rosalind is the greatest love of Amory's life. But that doesn't mean she's flawless. In fact, the first thing we learn about her is that she's flirty and kinda cruel with most of the men she meets. The book tells us early on that, "She is one of those girls who need never make the slightest effort to have men fall in love with them" (2.1.43).
And once these men have fallen in love with her, Rosalind tends to string them along for a while and then kick them to the curb because she's gotten bored with them. As she coldly tells one of her many admirers, "I have to be won all over again every time you see me" (2.1.198). How's that for high-maintenance?
We might even want to say that Rosalind is a spoiled brat. But the narrator is quick to say this isn't true. Instead, the narrator tells us that,
Her fresh enthusiasm, her will to grow and learn, her endless faith in the inexhaustibility of romance, her courage and fundamental honesty—these things are not spoiled. (2.1.43)
Ultimately, Rosalind is a lot like Amory. She has had a spoiled upbringing but has also come out of it with a sensitive soul. Unfortunately, she ends up breaking up with Amory—a guy she actually loves—because he doesn't have enough money or status. This experience basically breaks Amory's spirit and leaves him feeling totally cynical.
After all, if status and money can destroy true love, then what hope is there for the world?