To prepare roast: Mix together butter, garlic, sage and black pepper and set aside (can be made in advance and refrigerated up to one day, but warm to room temperature before proceeding).
Preheat oven to 350 degrees F.
Cut slits about an inch or so long and a half inch or so deep all over the top of the roast.
Spread butter mixture over the roast, using the handle of a spoon to get it into the slits you made earlier (very important).
(At this point, you can wrap roast in plastic and refrigerate overnight and up to 1 day.) Put prepared roast in a roasting pan, pour wine slowly over it, and cook for about 1 1/4 to 1 1/2 hours, depending on the size of the roast, basting about every 30 minutes or so with pan drippings.
Remove from oven, cover with aluminum foil and let rest for about 15 minutes.
After placing the roast in the oven, begin the tomato sauce by heating the olive oil and garlic together until golden and fragrant.
Add the tomatoes, salt and 1/4 cup finely chopped sage.
Stir well to combine, bring to a boil then reduce to simmer. Simmer no less than 30 minutes, the longer the better.
Just before serving add the remaining chopped sage and the butter.
After the roast has rested, slice and serve with the sauce drizzled over it.