He sets out the facts coolly and dispassionately.

他冷静、淡定地将真相合盘端出。

《柯林斯英汉双解大词典》

When an arguer argues dispassionately he thinks only of the argument.

当一个辩论者不动感情于争辩，他只是为争辩而辩。

youdao

I hope to equip you with the tools to do this effectively and dispassionately.

我希望用工具约束你有效地，冷静的去做。

youdao

After having an emotional outburst, you can temporarily lose trust in yourself to communicate dispassionately.

FORBES: Four Steps to Recover Credibility After You Cry At Work

So here are the questions: Can a justice have empathy and still rule dispassionately on the law?

CNN: Borger: 'Empathy' not a dirty word for a judge

Unlike George W Bush and John McCain, they argued, Mr Obama will approach foreign policy questions dispassionately.

BBC: Democratic Convention diary