He asked Amnon, "Why do you, the king's son, look so haggard morning after morning? Won't you tell me?" Amnon said to him, "I'm in love with Tamar, my brother Absalom's sister."
NIV
He said to Amnon, Why are you, the king's son, so lean and weak-looking from day to day? Will you not tell me? And Amnon said to him, I love Tamar, my [half] brother Absalom's sister.
AMP
And he said unto him, Why art thou, being the king's son, lean from day to day? wilt thou not tell me? And Amnon said unto him, I love Tamar, my brother Absalom's sister.
KJV