Tina Tomasino: German refugee
My best guess is that the Tina Tomasino character was actually German.
Although she spoke English slowly, she had no hint of an Italian accent like all the other Italian characters. All of them. Except her. Her hair was blonde, and although she tried to explain that away, Major Joppolo zings her by referring to her "dark skin" when she's obviously the palest person in town. And then, he just drops the issue.
Some folks have taken this to be horrible miscasting.
I'm not sure I like that explanation. The movie is otherwise quite good, so it's weird that this one single character would fail so catastrophically.
It makes PERFECT sense if she's a German refugee or something--a "good" German ex-pat who was the sweetheart of a "good" non-fascist Italian.
Maybe it was something that the audiences of 1945 wouldn't be receptive to, so it ended up on the cutting room floor.