As for the reason why Liu Chan chose to marry Zhang Fei's daughter instead of Guan Yu's daughter, we speculate that it may be related to Zhang Fei's appearance in "Romance of the Three Kingdoms", after all, the ancients often said, "A dragon gives birth to nine sons, each of which is different". On the other hand, Guan Yu, we are no strangers to his tall and strong body and beautiful beard, which shows that Guan Yu should be more handsome than Zhang Fei. But why did Liu Chan choose to marry Zhang Fei's daughter and not consider Guan Yu's daughter? It can be summarized into the following two main factors.
The primary reason is that Zhang Fei is kind to Liu Bei. In his early years, Zhang Fei gave Liu Bei financial support and helped Liu Bei start a business. It was against this historical background that Liu Bei decided to marry Zhang Fei's eldest daughter as the crown princess to express his gratitude. In addition, Zhang Fei's wife, Xiahou Shi, is the niece of Cao Wei's general Xiahou Yuan, and this marriage will not only consolidate the friendship between the two families, but also bring potential benefits.
As for the second reason, Guan Yu himself is a little arrogant and conceited. Because Liu Bei had a close relationship with him, Guan Yu's status in Shu was respected, and together with his own outstanding exploits, he formed a strong sense of superiority, so that he despised others. If Guan Yu's daughter becomes the queen of Shu Han, I am afraid that Guan Yu will be extremely arrogant when he walks in the future. For this kind of political marriage, weighing the pros and cons is often more important, so it is reasonable for Liu Chan to choose to give up marrying Guan Yu's daughter.