Yes, these are paired cities or twin cities as they're called in France, and that's just a way to promote themselves in other countries. In the case of Ronda it dates a few centuries and I always thought it was because of the legend mentioned above. Seems like it is a legend or rumor afterall. The mayor and his councillors couldn't tell me the real story behind the name. Not that it matters much anyways.
Enjoy your vacation for sure ☺