Jeff'S Fish Stew

Ingredients

• 1/4 cup olive oil
• 1 onion, diced
• 1 green bell pepper, diced
• 2 stalks celery, chopped
• 1 carrot, diced
• 3 cloves garlic, crushed and minced
• 1/2 teaspoon dried oregano
• 5 leaves fresh basil, chopped
• salt and ground black pepper to taste
• 2 (15 ounce) cans chicken broth, or more to taste
• 1 (28 ounce) can crushed tomatoes
• 1/2 cup dry white wine
• 1 1/2 pounds swordfish, cut into bite-sized pieces
• 2 (6.5 ounce) cans whole baby clams, undrained
• 1 tablespoon cornstarch, or as needed