Bring a large pot of salted water to a boil.
Heat a large non nonstick skillet over medium-high heat. Swirl in olive oil, and add onion, fennel and garlic. Sauté 5 minutes, until onion is translucent.
Add fennel seeds, oregano, pepper flakes, a pinch of salt and pepper, and pork to pan with onions and fennel. Stir to combine, and brown pork for 3-4 minutes, chopping it up with the edge of a stiff spatula. Pour in wine, and scrape up any bits stuck to the bottom of the pan, while wine evaporates.
Add tomato and stock, and bring to a boil. Reduce heat to medium-low, and simmer 15 minutes (or longer if you have time), stirring occasionally. While sauce is simmering, boil pasta, drain, and return to pot. Scrape sauce into pot with pasta, and toss to coat well.