Bring the wine and sugar to a boil in a small saucepan, stirring until the sugar is dissolved. Boil for 2 minutes. Remove from the heat.
Chop and combine the cantaloupe, strawberries, grapes, and mint in a large bowl. Pour the warm wine mixture over; toss to coat. Cover and refrigerate until cold, stirring occasionally, at least 2 hours.
Transfer to the fruit mixture to a wide jar with a tight-fitting lid. Keep chilled.