Terraria – Is the quote ‘Meet me behind [name of guide]’s house in three hours.’ From the traveling merchant true

It's just flavor text

All NPCs have various things they will say when you open the dialog box with them, and sometimes their lines will reference interactions with other NPCs. However, none of it has any actual significance to the game, and none of these interactions actually happen. The line in question is simply a random quote the Traveling Merchant says.