The best Italian food in South Bend is Parisi's located near ND campus. It is has a great atmosphere and great food. This is a finer dinning Italian ristorante... not a pizza joint. However, try the Pizza Margeritta appitizer (2-3 persons). It is the best I have every had... A must try. They serve pasta with seafood, veal and chicken entrees are outstanding!
The best Pizza in town is Rocco's (since 1951) and Bruno's (must go to the one on Prarie Ave.) Rocco's has fantastic pizza and sandwiches (try the Italian Hogie, it's huge)and Bruno Cataldo started working for Rocco when he came to the US from Italy and many many years ago opened his own place (Accually, I'm going there for lunch today) I have lived in NY and Chicago...Neither can compete with South Bend for Pizza because of these two. Polito's on Grape rd. does have great authentic NY Pizza. Owner Frank Polito, his wife Becky and brother-in-law Anthony relocated here from the Upper-East Side of Manhattan and Queens a few years back.
All the restaurant mentioned are all family owned by traditional families that settled here from Italy many years ago and continue to do what they do best.