Complex sentence: However, despite such brilliance, she has generally been unable to see through Clark's rather primitive disguise of glasses, and figure out that he is Superman, even when being the character that is most up close and personal with both Superman and Clark Kent.
Split into simpler sentences: However, despite such brilliance, she has generally been unable to see through Clark's rather primitive disguise of glasses, and figure out that he is Superman. Despite being the character that is most up close and personal with both Superman and Clark Kent.