Combine softened cream cheese, ricotta cheese, and pecans. Wash pears; pat dry. Core each of the pears, leaving a center hole about 1 inch in diameter. Fill each pear center with the cream cheese-nut mixture. Chill. Make sauce by pressing raspberries through a sieve to remove seeds. Combine raspberries and juice with water, sugar, and cornstarch. Cook and stir till thickened. Chill. To serve, cut pears crosswise into 1/4-inch slices. For each serving, spoon a little sauce onto dessert plate, and place 4 or 5 pear slices on top of sauce.