Valmiki Ramayana Yuddha Kanda Sarga 92 Shloka 13

दुष्करकर्मणा one who does What is difficult for others, परमकळ्याणम् deed which is extremely auspicious (beneficial), कर्म action, कृतम् done, अद्य now, पुत्रे son, हते killed, युधि in battle, रावणम् Ravana, निहतम् also killed, मन्ये think

"You have done an extremely beneficial task which is difficult for others to do. I think Ravana is killed in the battle with your action of killing Indrajith."