Complex sentence: Born Mildred Elizabeth Sisk in Portland, Maine, she took the name Mildred Gillars as a small child after her mother remarried and moved to New York City, where young Mildred dreamed of becoming an actress, but met with little success.
Split into simpler sentences: Born Mildred Elizabeth Sisk in Portland, Maine, she took the name Mildred Gillars as a small child after her mother remarried. Gillars afterwards moved to New York City, where she dreamed of becoming an actress but met with little success.