Simple syrup : Combine 1 cup sugar and one cup water in a medium saucepan over medium heat. Stir until sugar dissolves. Increase heat and bring to a boil. When mixture comes to a boil, lower heat and simmer for 3-5 minutes. Remove from heat and let cool.
Place mango cubes, simple syrup, lime juice and zest in a blender or food processor and puree until smooth.
Freeze the puree in an ice cream maker according to manufacturer's directions.
Spoon sorbet into freezer container, cover and freeze for 6-8 hours.
Spoon into bowl and garnish with fresh raspberries. The sorbet will last in the freezer up to one week.