Complex sentence: Through her large eyes, Keane aimed to express Rapunzel's "irrepressible quality", a trait that was also discovered in Mandy Moore's voice, which allowed Keane to use her as inspiration.
Split into simpler sentences: Through her large eyes, Keane aimed to express Rapunzel's "irrepressible quality". A similar quality was found in Mandy Moore's voice, which allowed Keane to use her as inspiration.