On the morning of the fourth day, the little prince reveals that he loves sunsets, and says to the narrator, “Come let us go look at a sunset now” (6.1).
Then, the narrator has to explain to him that on Earth, sunsets only happen in the evenings.
Of course, that’s not how it works where the prince is from. Because his planet is so tiny, he can see a sunset at any time—all he has to do is move a few steps. One day, says the little prince, he watched forty-four sunsets.
The prince says that he loves watching sunsets when he is sad.
The narrator realizes then that the prince is melancholy. When he asks him about it, though, the prince says nothing.