In a large Dutch oven, over medium/high heat, brown and crumble the Italian sausage.
Add the chopped fennel, onion, salt and pepper into the pot. Cook stirring occasionally for approximately 5 minutes.
Reduce the heat and add the garlic, and tomato paste. Cook, stirring occasionally for approximately 2 minutes.
Add the cannellini beans, white wine, chicken stock and water to the pot.
Simmer the soup over medium/low for approximately 15-20 minutes to marry the flavors.
Season with additional salt and pepper to taste.
Ladle the soup into bowls and garnish with fresh fennel fronds, if desired.