Because they already have a second person.

Do not waste your sincere feelings
For a person who did not know the respect
Forget my sister, so that the pain will follow the wind clouds to the end of heaven.
So why try to love each other
Any sadness will pass
Because I know you are suffering a lot.
Do not worry about that person anymore
Do not suffer for it anymore
This love I think you should stop
Because they already have a second person.
You are stupid to try to love a person
Do not cry anymore
Because you are here now
And he does not bring you joy
Then let each other pain.