The prince’s love for his flower causes him much pain and heartbreak. Let’s try to understand her better to see what all the fuss is about.
The flower grows from a strange seed that somehow lands up on the prince’s planet. The first thing we learn about her is that she is bee-yoo-ti-ful. When she emerges from her bud and the prince sees her for the first time, he cannot restrain his admiration and exclaims: “Oh! How beautiful you are!” (8.7).
And the flower sweetly replies: “Am I not?” (8.8). The prince realizes then that she isn’t “too modest” but he finds her “moving” and “exciting” (8.9). But over time, though he tends to her carefully and responsibly, the flower preens and fusses and begins “to torment him with her vanity” (8.12). She complains about the weather on the prince’s planet, and insists that he place her under a glass globe every night; and because she has “a horror of drafts” (8.17), she demands that he build her a screen. She even fakes a cough just to make the prince feel guilty.
Actually, this one has four thorns. She brandishes them and proclaims, “Let the tigers come with their claws!” (8.13). Now, of course, her little thorns would be no defense against tigers, and we know they don’t even protect her from the cold, or drafts, or caterpillars. In fact, the flower seems defenseless and susceptible—and yet, she shows off her thorns and puts on a superior attitude.
Why does she do this?
Well, the little prince calls her “naïve” (9.15), and she is. She is also a sensitive little thing—easily hurt and susceptible to animals and drafts. And she is rather insecure, we think; there is nothing she likes better than hearing her beauty praised. To top it all off, she is “a proud flower” (9.17)—she doesn’t like to expose her vulnerability.
So her bluster is really her defense mechanism. Later on, the prince realizes this and tells the narrator:
“I ought to have judged by deeds and not by words. She cast her fragrance and her radiance over me. I ought never to have run away from her…I ought to have guessed all the affection that lay behind her poor little stratagems.” (8.27)
The flower’s vanity and demands get too much for our prince, and he decides to leave his planet.
Just before the prince leaves, the flower is full of “quiet sweetness” (9.9) and tells him that she doesn’t need the protective glass globe she once demanded.
Instead, she straight up admits her feelings:
“Of course I love you,” the flower said to him. “It is my fault that you have not known it all the while. That is of no importance. But you—you have been just as foolish as I. Try to be happy…”(9.10)
This is certainly a complete contrast to her previous behavior! It is a very mature and selfless thing to say. The flower admits her love and wishes the prince happiness—she has definitely grown more mature and wise. Most people (us included) wouldn’t handle a breakup that well.
Many critics consider the flower to be based on Saint-Exupéry’s real-life wife, Consuelo. Their relationship had never a dull moment—which is a polite way of saying they yelled at each other a lot and threw dinner plates often, but were also madly in love. (Source) Consuelo even wrote a book about their marriage and titled it The Tale of the Rose.