Combine cranberries, water, and sugar in a saucepan and bring to a boil. Cook until berries are splitting open and tender, about 10 minutes. While cranberries cook, pour cherry-flavored gelatin mix into a casserole dish. Pour cooked cranberry mixture over gelatin in the casserole dish and stir to dissolve and mix evenly. Place in the refrigerator until gelatin is set, about 1 hour. Add pineapple, pears, and pecans. Stir and serve.