Complex sentence: In the Underworld, when she is judged, she is told that if she hadn't died, she would have grown up and married Sammy, her childhood friend and boyfriend (he is now known to be Leo Valdez's ancestor).
Split into simpler sentences: In the Underworld, when she is judged, she is shown what her life would have been if she hadn't died. If she had lived, she would have grown up and married Sammy, her childhood friend and boyfriend (he is now known to be Leo Valdez's ancestor).