Berean Study Bible
Amnon was sick with frustration over his sister Tamar, for she was a virgin, and it seemed implausible for him to do anything to her.

King James Bible
And Amnon was so vexed, that he fell sick for his sister Tamar; for she was a virgin; and Amnon thought it hard for him to do any thing to her.

American Standard Version
And Amnon was so vexed that he fell sick because of his sister Tamar; for she was a virgin; and it seemed hard to Amnon to do anything unto her.

Darby Bible Translation
And Amnon was so vexed, that he fell sick for his sister Tamar; for she was a virgin; and it seemed difficult for Amnon to do the least thing to her.

Douay-Rheims Bible
And he was exceedingly fond of her, so that he fell sick for the love of her: for as she was a virgin, he thought it hard to do any thing dishonestly with her.

English Revised Version
And Amnon was so vexed that he fell sick because of his sister Tamar; for she was a virgin; and it seemed hard to Amnon to do any thing unto her.

Young's Literal Translation
And Amnon hath distress -- even to become sick, because of Tamar his sister, for she is a virgin, and it is hard in the eyes of Amnon to do anything to her.