Here’s the only tricky part: most tomato sauces come pre-loaded with garlic, onion, or basil. Tomato paste is pure, unadulterated tomato. It’s innocent. It has no opinions.
So when you mix your paste-and-water solution, you need to add your own seasonings. A pinch of salt, some dried oregano, a crushed garlic clove, or a sprinkle of sugar to cut the acidity.
Don’t be shy. Taste as you go. You’re the captain of this sauce ship now. And if you accidentally add too much garlic? Congratulations, you just made “robust” sauce. That’s a fancy word for “I messed up, but it tastes great.”