In the 80s, I have read a children's book about a boy riding in a caravan which is joint by a traveler who is a story-teller and invents a story together with the boy. At the end, this story turns out to be essentially true and the story-teller is the hero of this invented story who rejoins his love who he previously lost after valuing gold higher than water to irrigate the desert.
The book was from the youth section of a public library (that does not exist anymore) and it was in German. However, it is very likely that it was translated because most books in that section were and googling phrases from the book in German gives nothing. It is quite likely that it was translated from English, but this is not certain.
I would be happy to find this book again.