The most common reason given for Italians emigrating to America was to find a better life or in some cases for men, to avoid the Italian Army draft. In Italy, it was common for families to set up marriages for their children. Therefore, in the case of single adult Italian women emigrating to America, I suspect the reason was that the family failed in their attempt to line up a man to marry them. Italian women were expected to raise families of lots of children and consequently not work so coming to America to find a better work life seems unlikely. I'm guessing that these single Italian women, whose own family stayed in Italy or just a sibling or two emigrated to America emigrated to America in hopes of having better luck in finding a husband. Is there any data indicating that was the reason in many cases?
Ron