Chop the watermelon and cut the apple into bite-sized pieces. Add the chopped apples and 2 cups of the watermelon to the bottom of a large pitcher. Sprinkle them with sugar and stir gently. Let them stand for 20 minutes at room temperature.
After 20 minutes, add the remaining 6 cups of watermelon to a blender and blend until juiced. Pour through a strainer into the pitcher. Add the the white wine and brandy, fresh mint and thinly sliced lime rounds. Stir and refrigerate for 1 hour, or as long as 4 hours. (Don’t go beyond 4 hours or the fruit texture starts to degrade.)
Pour the watermelon sangria into ice-filled glasses. Add fruit to each glass, preferably on long skewers for easy snacking.