Why did Kim Jonghyun end his life?

Because he has inner problems and suffers from depression.

On 20 17 12 18, Kim Jong-hyun committed suicide by burning charcoal in a hotel-style apartment in Seoul. Cardiac arrest, was sent to the Affiliated Hospital of Jianguo University for emergency cardiopulmonary resuscitation. However, he did not regain consciousness and was declared dead by the hospital. When the investigators arrived at the apartment, they found the briquettes burning on the pan, thinking that they were killed by charcoal burning. The police said that at the request of Zhong Xuan's family, no autopsy would be conducted.

Extended data:

Kim Jong-hyun is a Korean male singer, songwriter and music producer. Before his death, he was a member of SHINee, a five-man male singing group under SM Entertainment, and served as the first lead singer of the group.

According to the police, on February/KOOC-0/7/KOOC-0/8+08 (Korean standard time), Kim Jonghyun was found unconscious in an apartment in Cheongdam-dong, Gangnam-gu, southeast Seoul. After Kim Jonghyun's death, his good friend Nine of DearCloud posted a suicide note from Zhong Xuan to her on Instagram, which mentioned that she "swallowed up" his depression and said that she was "mentally ill".

Baidu Encyclopedia-Kim Jonghyun