During the Three Kingdoms Period, Liu Bei heard Zhuge Liang was very talented. He hoped Zhuge Liang would come and work for him, so one day, he took gifts to Longzhong (the house of Zhuge Liang) to invite the talented man to the court. When he got there, the servant told Liubei that Zhuge Liang was not home. Liubei had no choice but to return home in disappointment.
Later, this time with Guan Yu and Zhang Fei, Liu Bei went back to Zhuge Liang's home, braving the strong wind and snow. But the servant again told him that Zhuge Liang was not in. Guan Yu and Zhang Fei became very angry. They persuaded Liu Bei to never return, but Liu Bei was insistent.
When they arrived the third time, Zhuge Liang was sleeping. Liu Bei didn't want to disturb him, and so waited until he woke up. Zhuge Liang saw Liu Bei's determination and sincerity, and agreed to assist Liu Bei. Zhuge Liang would eventually become one of the most famous prime ministers in history.
The original meaning of "三顾茅庐" refers to Liu Bei asking Zhuge Liang to help him three times. Now, it's often used as a metaphor to describe when a person sincerely invites somebody to do something repeatedly.
例句:
1、他三顾茅庐,才请到了这位教授为我们开讲座。 After our repeated requests, the professor finally gave us the lecture.
2、诸葛亮终于被刘备三顾茅庐的精神打动了。 Zhuge Liang was touched by Liu Bei's persistence to ask his help.