Heat oil in a skillet or saucepan over medium heat. Saute onion until translucent and lightly caramelized, about 5 minutes. Stir in garlic and cook for about 2 minutes.
Stir in wine, sweetener, basil, red pepper flakes, Italian seasoning, black pepper, salt, tomato paste, diced tomatoes, and tomato sauce. Bring to a boil, reduce heat to medium, and simmer uncovered for about 15 minutes.