He is pure in [of] heart.

他心灵纯洁。

《新英汉大辞典》

In everything you demonstrated yourselves to be pure in the matter.

在这一切事上你们都表明自己是洁净的。

youdao

These are the beatitudes: Blessed are the pure in heart for they shall see God.

下面是祝福：,“心灵洁净的有福了，因他们得见上帝。

youdao

However,the band is clear about staying pure in the music business.

VOA: special.2010.04.16

Investment banks are very different in that a pure investment bank does not accept deposits and it doesn't make loans; it's an underwriter for securities.

投资银行是完全不同的,单纯的投资银行既不吸收存款,也不发放贷款,投行是证券承销商

耶鲁公开课 - 金融市场课程节选

It is autonomous in the sense that it is a pure, uncluttered and uninfluenced declaration of fact or falsehood.

科学是自主的，因为,科学就是单纯的,不受外界影响的，关于真伪的论断。

耶鲁公开课 - 文学理论导论课程节选

It's been called the pure war, but nothing's pure in life, I've decided.

CNN: He remembers Papa

Pure in Heart: The Life and Legacy of Lon Chaney, Jr.

ENGADGET: Dracula, The Mummy and six other horror classics coming in a Blu-ray set October 2nd (video)

For weeks after, that first image of my beautiful son as he emerged -- eyes closed, still, so pure in his newness -- was emblazoned on the inside of my eyelids.

CNN: Delivering my son: 'Breathe, baby, breathe!'