1Cut the watermelon into small chunks and remove any seeds.
Peel and chop the mango into small pieces.
Place the watermelon chunks and mango pieces into a blender.
Add the sugar and lemon juice to the blender.
Blend the mixture until smooth.
Pour the mixture into a shallow container and place it in the freezer.
Freeze for about 2-3 hours, stirring every 30 minutes to break up any ice crystals.
Once the sorbet is firm and smooth, scoop it into bowls and serve immediately.