In the bowl of an electric mixer with the whisk attachment, whip goat cheese until soft and creamy. Add finely diced mango and pomegranate arils and fold in gently.
Place the whipped goat cheese mixture on a piece of plastic wrap, and roll to form a log, twisting the ends tightly. Chill until firm 3-4 hours, or longer.
In a small pan, melt butter over medium high heat. Add sage leaves and fry, about 1-2 minutes per side or until crispy. Remove from the heat and drain on a paper towel.
Crush the fried sage leaves into bits and mix into the chopped pistachios. Spread the mixture onto a clean work surface and roll the chilled cheese log into the nut mixture until all sides are evenly coated. Wrap and chill – allow the cheese to come to room temperate when serving for easy spreading.