Image: Rebel Wolves / Bandai NamcoOfficial screenshot from Rebel Wolves / Bandai Namco.
Tour Guide Training asks you to visit every village in Vale Sangora, eight in total. One of them stays closed until you finish certain quests, which is why fewer than a third of players have it.
Travel to each of the eight villages in Vale Sangora. The trophy pops when you enter the last one.
If you have seen seven villages and the trophy has not popped, the missing one is probably the settlement that opens through quests. Push on with side quests and it will become reachable.