I am kind-hearted, but the world is so cold.
But do good deeds and remain committed to them throughout your life.
Meaning: My nature is kind, but I am helpless and so worldly. You should do more righteous deeds and be good at the present moment, and never change your mind. There are many sentences of this form: I am kind-hearted, but I have fallen into the world.
I am kind-hearted, but God does not allow it.
I am kind, but the world is dangerous.
I am devoted to love, but I am materialistic.
I am a hero, but a traitor is in charge.
There is also the TV series "I Am Kind"