In a large mixing bowl, combine the sliced strawberries, blueberries, and diced watermelon.
Gently fold in the mini marshmallows.
In a separate bowl, whisk together the whipped cream and honey until well combined.
Pour the whipped cream mixture over the fruit and marshmallows, and gently toss to coat everything evenly.
Transfer the fruit salad to a serving bowl or individual cups.
Garnish with fresh mint leaves if desired.
Chill in the refrigerator for at least 30 minutes before serving for the best flavor.