Combine the pear juice, sugar, pears and lemon zest and juice in a large saucepan. Cook over medium-high heat until the pears are fork-tender, about 15 minutes. Using a slotted spoon, remove the pears from the liquid and set aside. Continue cooking the liquid until syrupy and reduced by half, about 15 minutes more. Let cool slightly. Puree the pears and the pear syrup in a blender until smooth. Pass through a fine sieve into a bowl. Chill in the freezer until partially frozen, about 1 hour. Beat the pear mixture with a whisk until creamy. Return the bowl to the freezer and repeat the whisking process every hour until the sorbet has a smooth, luscious texture (about 4 hours total). To serve, scoop the sorbet into bowls and garnish with candied ginger and basil.
You can use an ice cream maker if you have one; follow the manufacturer's instructions.