When people talk about "romance-speaking Europe," they're talking about countries where people speak languages that evolved from Latin, which was the language spoken by the ancient Romans.
This includes countries like France, Spain, Italy, Portugal and Romania. These languages all sound different and have their own unique words, but they're all related to each other because they all come from the same ancient root.
People who speak these languages have been sharing ideas and cultures for hundreds of years, which means there are some things that are similar between these countries even though they are separate. For example, many of these countries share a love of good food, art, music, and history. And because they all speak a somewhat similar language, they can communicate with each other more easily than with speakers of languages from other parts of the world.
So when people talk about romantic-speaking Europe, they're really highlighting all the things that make these countries unique and interesting, while also noting that they have a lot of similarities because they share the same language roots.