Guan Yu is a well-known figure of the Three Kingdoms of the late Han Dynasty, and his loyalty and righteousness are worshipped as gods. However, Guan Yu has a serious flaw in his personality, that is, he is lonely and arrogant and difficult to get along with people. One of the most obvious examples is Guan Yu's refusal to marry his daughter to Sun Quan's son.
The "Three Kingdoms Zhishu Shu Guan Yu Biography" records: "First, Quan sent envoys as sons and daughters, Yu scolded and insulted his envoys, and did not allow marriage, and Quan was furious. What is said here is that Sun Quan sent emissaries to Guan Yu to discuss marriage (to let his son marry Guan Yu's daughter), and Sun Quan's emissaries soon after seeing Guan Yu show their intentions, rejected Sun Quan's request and scolded Sun Quan's emissaries. When the emissary returned, he told Sun Quan about his insults by Guan Yu, and Sun Quan was furious when he heard about it. We say that Sun Quan and Liu Bei were allies at that time, but Guan Yu, as a general under Liu Bei, was arrogant and rude to Sun Quan's emissaries, which is indeed very unwise.
The general view is that Guan Yu's disagreement with this marriage can be completely rejected by euphemism, there is no need to insult Sun Quan's emissaries, and judging from Guan Yu's behavior, he made such a move entirely out of arrogance and arrogance in character. In fact, I think guan Yu's insult to Sun Quan's emissaries is wrong, but he also has his own grievances. Why? We also have to start from Sun Quan's motivation for finding Guan Yu to marry.
Sun Quan's move to marry Guan Yu was obviously deliberately trying to woo Guan Yu, but he did not take into account that Guan Yu had to be cautious about this marriage (or that Sun Quan took into account Guan Yu's scruples but deliberately did it). At that time, Liu Bei was in Shudi, while Guan Yu was alone in Jingzhou. It can be said that Liu Bei handed over his base camp to Guan Yu, and Guan Yu's position was both important and sensitive. As Liu Bei's general, if Guan Yu agreed to marry Sun Quan, it would mean that Guan Yu would be bribed by Sun Quan. Imagine if Liu Bei knew that Guan Yu and Sun Quan were married to his family, would he not react to this matter?
It can even be said that Sun Quan's marriage to Guan Yu is actually not at ease, putting Guan Yu in a very awkward position. Sun Quan understood that if Guan Yu accepted his request for marriage, then the relationship between Liu Bei and Guan Yu would be rifted. And even if Guan Yu didn't agree to just a euphemistic refusal, Liu Bei would be suspicious after learning about it. Perhaps Guan Yu had seen through Sun Quan's tricks, and at this critical time he had to make his position clear. So how do you make your position clear? It is impossible to agree to Sun Quan's request for marriage, and refusing too euphemistically will seem to drag the mud and water. Therefore, Guan Yu could only take an extreme way to take a stand, that is, to scold Sun Quan's emissaries.
Guan Yu was the town guard general of Jingzhou, and he should not have contact with any princes. At that time, the marriage between the princes and generals was not an ordinary marriage, it meant a profound and mutual alliance. Guan Yu could not have been unaware of this, so although he scolded the Eastern Wu emissaries for their uncivilized behavior, it showed his political cleverness.