Pour your juice into a saucepan. Add in 2 TB of gelatin and stir until the gelatin is dissolved. Turn on heat to medium and let simmer for about 10 minutes. Turn off heat and let sit for 1-2 minutes. Don't let it sit long or it will start to clump. Stir and taste. Add and mix in sweetener if you desire. Pour mixture into a jello mold (any glass bowl will work... even ice cube trays!) Put jello into refrigerator and let sit for at least 3-4 hours. Better to leave overnight.