Cut the pork tenderloin into bite-sized pieces.
Finely chop the onion, carrot, and celery.
Heat olive oil in a pan and sauté the vegetables.
Add the pork tenderloin and cook until the surface is browned.
Pour in tomato sauce and a suitable amount of water.
Season with herbs, salt, and pepper.
Simmer over medium-low heat until the ingredients are tender.
Transfer to a plate to serve.