Slice golden watermelon in quarters. Cut the flesh from the skin and rind then transfer to a food processor or blender. Process until smooth.
Pour golden watermelon puree through a fine mesh basket strainer into a large measuring cup (4- or 8-cup), using a spoon to expedite the process. If you don't have a large measuring cup, strain into a large bowl with a pour spout then measure in batches. Take note of how much watermelon juice you have (for me, 1 watermelon produced about 2 1/2 cups of juice) then pour juice into a large bowl.
Measure out an equal amount of simple syrup. The ratio of juice to simple syrup should be about 1 to 1. Pour 3/4 of your simple syrup into the juice, stirring to combine. Taste for sweetness and add more simple syrup if needed (I used all of the simple syrup).
Cover the large bowl and transfer to the refrigerator to chill thoroughly.
Freeze sorbet base in an ice cream maker according to the manufacturer’s instructions. Finish by freezing the sorbet until hard or enjoy soft immediately.
To make simple syrup: Warm equal parts white sugar and water over medium heat (you'll need 2 - 3 cups of sugar and 2 - 3 cups of water), stirring until sugar is completely dissolved. Bring mixture to a boil, bubble for 1 minute, then remove from heat. Let cool before using.