Why did Kim Jonghyun end his life?

Because Kim Jonghyun suffers from depression.

Kim Jonghyun confided that he was suffering from depression. In addition to telling his sister about it, he also told his friends about it. Kim Jonghyun doesn't have any problems in his personal life. He just feels that he can't meet the expectations of people around him and feels that he is incompetent, and the pressure is gradually increasing. It slowly became more and more painful and eventually turned into severe depression.

On December 18, 2017, Kim Jong-hyun committed suicide by burning charcoal in the serviced apartment he just moved into in Seoul. He died after receiving first aid at the age of 27.

Extended information:

After Kim Jonghyun passed away, his friend Nine from the band DearCloud published a suicide note that Jonghyun had entrusted to her on Instagram, which mentioned that "devouring" him Depression, saying that "problems started from within".

On December 18, 2018, in order to commemorate Kim Jonghyun, SM officially broadcast a 47-second video, which mainly showed the dazzling and beautiful moments of Kim Jonghyun in the past. He also wrote the words "Jonghyun, I will always miss you and always love you, SM family." Not only did SM lose a talent, many fans also lost their idols. Fans miss Kim Jonghyun very much.