It is arguable that the truth about true love that is presented in Oscar Wilde's short story "The Nightingale and the Rose" is that the idea of love, of true love, is different from person to person. However, only those who believe that love is not just caprice, are capable of even sacrificing their lives in the name of it.
In this story we have two characters who see love quite differently. First, we have the Oxford bachelor, a student who merely thinks that he is madly in love with a girl. He needs a red rose to give to the girl so that "she would dance with him til dawn" at the Prince's ball.
But the student has no red roses in his garden. What is he to do?
Here comes the Nightingale, a bird who has been listening to the woes of the student and truly believes that he is just a true believer in love, just like her.
Here at last is a true lover," said the Nightingale. "Night after night have I sung of him, though I knew him not: night after night have I told his story to the stars, and now I see him. His hair is dark as the hyacinth-blossom, and his lips are red as the rose of his desire; but passion has made his face like pale ivory, and sorrow has set her seal upon his brow.
Hoping to fulfill the dream of the student, the nightingale asks for a red rose everywhere, but finds none. It is here when she does the unthinkable: she sacrifices herself to bring the red to a white rose using the blood from her own heart.
This is what the truth is: that those who believe in what love really is, and what it takes to really feel it, will stop at nothing to achieve it. Unfortunately, the nightingale is never aware of the superficial nature of the student's true affections.
When the student goes to the Prince's ball with the red rose that he finally "finds", he is shun by the girl. The flower does not go with her dress, she says. And she would have preferred jewels, instead of flowers. Plus, the student is a nobody in her eyes. Why even bother looking his way?
Here we see the difference between the bachelor and the nightingale: to the bird, love is more important than anything. The love that the nightingale bares for the student and for her idea of love is overwhelming. She gives it all to him, out of that deep sentiment that she has cultivated. She also believes in what she does. Those who believe see no sacrifice.
Meanwhile, unaware of the huge sacrifice that has been done for him, the bachelor simply says:
"What I a silly thing Love is," said the Student as he walked away.
"It is not half as useful as Logic, for it does not prove anything, and it is always telling one of things that are not going to happen, and making one believe things that are not true. In fact, it is quite unpractical, and, as in this age to be practical is everything, I shall go back to Philosophy and study Metaphysics
Therefore, although all of us think that we have loved, very few have loved truly and stopping at nothing. Love has many levels, but only those who have reached its cuspid can actually tells us what it really is.