Complex sentence: Hoping to weaken the Tyrells, Cersei dispatches Ser Loras Tyrell to siege Stannis Baratheon's forces on Dragonstone; as a result, thousands are killed, and Ser Loras is gravely injured.
Split into simpler sentences: Hoping to weaken the Tyrells, Cersei dispatches Ser Loras Tyrell to siege Stannis Baratheon's forces on Dragonstone. As a result, thousands are killed, and Ser Loras is gravely injured.