It is true that doctors have a high salary. But their work is extremely hard.
It would not be possible to do such work without a high salary!
ご質問ありがとうございます。
"It is true that doctors have a high salary."=「医者が高収入を得るというのは事実です。」
"But their work is extremely hard."=「でも、医者たちの仕事はとても大変です。」
"It would not be possible to do such work without a high salary!"=「高収入でなければそのような仕事をするのは不可能です!」
ご参考に。