Since Sun Shang Xiang heard the rumors about her future marriage would be Liu Bei, she disagree with Lady Wu for getting marry with an aged man. Lady Wu told her daughter to decide about Liu Bei if she's not willing to married. Sun Shang Xiang was only 18 years old, therefore Liu Bei was 48.
As both Lu Su and Zhou Yu gave suggestions to Sun Quan, Lu Su gave an answer that not to bring any harm to Liu Bei, therefore Sun Quan disagree with Lu Su and expelled his service from the Wu and the millitary. Lu Su had no choice but to inform Liu Bei that Zhou Yu was planned to murder him in the temple of Wu. Liu Bei plans not to leave the states of Wu, but to take his chances to be close relatives with the Wu's family.