Complex sentence: Putnam helps Earhart write a book chronicling the flight, much like his earlier triumph with Charles Lindbergh's "We", gradually falling in love with his charge, and they eventually marry, although she enacts a "cruel" pledge as her wedding contract.
Split into simpler sentences: Putnam helps Earhart write a book chronicling the flight, much like his earlier triumph with Charles Lindbergh's "We". Earhart gradually falls in love with Putnam and they eventually marry, although she enacts a "cruel" pledge as her wedding contract.