Complex sentence: In the main event, Roman Reigns would defeat Dean Ambrose to win the vacant WWE World Heavyweight Championship however Sheamus cashed in his Money in the Bank contract and defeated Reigns to win the title.
Split into simpler sentences: In the main event, Roman Reigns defeated Dean Ambrose to win the vacant WWE World Heavyweight Championship. Sheamus then cashed in his Money in the Bank contract and defeated Reigns to win the title.