Complex sentence: In Egyptian mythology, Aaru (alternatives: "Yaaru", "Iaru", "Aalu"), is the heavenly underworld where Osiris ruled; souls which weighed less than the Feather of Truth were sent to Aaru to exist in pleasure for all eternity.
Split into simpler sentences: In Egyptian mythology, Aaru (alternatives: "Yaaru", "Iaru", "Aalu"), is the heavenly underworld where Osiris ruled. Souls which weighed less than the Feather of Truth were sent to Aaru to exist in pleasure for all eternity.