Go now, Mother. Tell your sons nothing. Fight me. I will kill Arjuna or Arjuna will kill me. That is my gift to you: your five sons will live. I will aim only for the one who is not your son by Kunti's womb—no, wait. Arjuna is my brother too. So I will fight him as a Kshatriya fights a Kshatriya. Let fate decide."
(Embracing his feet) "Then I will curse myself every day of my life. But promise me, Karna—the world will know the truth after you die. People should know that the great warrior Karna was a son of the Sun, not a Suta." karna kunti sambad english translation
If I join the Pandavas now, the world will say: 'Karna is a traitor who changes sides for his mother's tears.' I cannot betray Duryodhana's salt. But... I will give you this promise: I will not kill any of your other sons. I will only fight Arjuna. Either he or I will die. You will still have five sons left, Mother. You will not be childless." Go now, Mother
(Stunned, letting go of his arrow and water pot. He laughs bitterly) "What is this, Mother? You call me a Suta-putra (son of a charioteer) all my life, let me be ridiculed by the world, let me be denied education by Parasurama's curse, let Draupadi call me a 'Suta's son' and refuse me at her swayamvara... and now, on the eve of the greatest war, you call me your son? What is your purpose?" I will kill Arjuna or Arjuna will kill me