In a medium saucepan over medium-high heat, combine sugar, 1/2 cup watermelon pulp, and salt; bring to a boil. Boil 30 to 45 seconds sugar completely dissolves. Remove from heat and let stand approximately 10 minutes. If making ahead, store in refrigerator
To the remaining 4 cups pureed watermelon pulp, add the above watermelon/sugar syrup, lemon juice, and Anisette Liqueur; stir until thoroughly blended. The Anisette (or any other type of alcohol) is the secret to a soft sorbet. Alcohol itself does not freeze and adding a little bit keeps the sorbet from doing the same.
Ice Cream Maker - Transfer mixture to ice cream maker, process according to manufacturer's instructions.
Freezer Method - Pour into container, cover, and place mixture in the freezer. When it is semi-solid, mash it up with a fork and refreeze again. When frozen, place in a food processor or blender and process until smooth. Cover and refreeze until serving time. This is the method I like to use.
Can be prepared 3 days in advance. Cover and keep frozen.
Makes 4 to 6 servings.