Complex sentence: He believed that trillions of dollars of foreign investment funds would instantly flow into the United States to be invested in new facilities by foreign investors and corporations sparking a new economic boom, and a massive increase in employment.
Split into simpler sentences: He believed that trillions of dollars of foreign investment funds would instantly flow into the United States. It would be invested in new facilities by foreign investors and corporations sparking a new economic boom, and a massive increase in employment.