Preheat the oven to 425 degrees F. Line a rimmed baking sheet with parchment paper.
Arrange the pancetta in a single layer on the prepared baking sheet. Bake until light golden brown and crisp, about 14 minutes. Transfer the pancetta to a paper towel-lined plate to drain. Finely chop the pancetta.
Combine the honey and 2 teaspoons of the sliced sage in a small, microwave-safe bowl. Microwave until it just begins to simmer, about 30 seconds (be careful, it can easily boil over). Cool to room temperature, then strain through a fine-mesh sieve.
Spoon a little bit of the sage honey onto the flat side of a melon cube and mound a little bit of pancetta on top. Put on a serving plate and repeat with the remaining melon cubes. Sprinkle with the remaining teaspoon sliced sage and garnish the plate with the sage sprig. Serve immediately with toothpicks on the side.