South Italy/America

South Italy/America is a semi-popular pairing found in the fandom. In Hetalia: World Stars, it's revealed that Romano lived in America's place for a while and worked for him. Because of this, Romano knows America quite well, which is shown in one strip in which he and Veneziano prepare food for America.

Fan Speculation
It is thought of as the same concept as Spain/South Italy. America, similarly to Spain, is very cheerful and affectionate, whereas Romano is a tsundere character.