The first phrase I have for you is " He's a rough diamond" .

我要给你的第一句话是“他是个外粗内秀的人”。

He is a rough diamond. With proper training, he would be an asset for the company.

他是个未经雕琢的人，经过适当的培训，他会成为公司的宝贵财富。

You make Mr Painswick sound rather a rough diamond, Lady Grantham.

老夫人口中的姑爷倒像块浑金璞玉。

Back in 2003 when the crime took place, three billion dollars of diamond sales were made in just this tiny area and over eighty percent of all the world's rough diamonds will pass through here.

早在 2003 年，当犯罪发生时，这片小区域的钻石销售额就达到了 30 亿美元，世界上 80% 以上的原钻都会在这里经手。