The quote means that the desert can be a place of beauty, despite its barrenness, because somewhere within it can be found a source of life and refreshment. The “well” mentioned in this line can refer to a literal, physical well of fresh water, or it can be a metaphor for other sources of sustenance, such as a spiritual teaching or philosophy. In either case, the little prince is saying that, although the desert can appear daunting and inhospitable, there is value and beauty to be found within it.