Heat pineapple, juices, garlic and jalapeno pepper to boiling in a medium saucepan; reduce heat and simmer, uncovered about 5 minutes.
Stir in cilantro; heat to boiling.
Mix cornstarch and cold water, stir into boiling mixture.
Boil, stiring constantly, until thickened.
Remove from heat; cool 2-3 minutes.
Stir in nutrasweet, season to taste with salt and pepper.
Serve warm over fish or pork.