Complex sentence: In the summer of her fifth-year at Ueno Girls High School, under her uncles management she was married to a man named Fukutaro, Ito only agreed because he had just returned from America, where she hoped to go.
Split into simpler sentences: In the summer of her fifth-year at Ueno Girls High School, under her uncle's management, she was married to a man named Fukutaro. Ito agreed to the marriage because Fukutaro had just returned from America, where she hoped to go.