I'd like to talk to you about a personal matter.

我想和你谈点私事。

《牛津词典》

Motivation is also a personal matter.

积极性也是一个个人问题。

youdao

It's a personal matter. Please respect their decision.

这是一件私人的事情，请大家尊重他们的决定。

youdao

Maya Lin has said that death is a private and personal matter.

VOA: special.2009.05.06

Although I'm inclined to think that the body theory may be the best view about what's the key to personal identity, I'm also inclined to think it doesn't really matter.

虽然我倾向于觉得身体理论,也许是解释个人认同感的关键观点，我同样觉得，这其实根本无关紧要。

耶鲁公开课 - 死亡课程节选

But in Ankara he said he will set his personal views aside, and let the Turks and Armenians settle the matter themselves.

VOA: standard.2009.04.06

Faith is no civil contract, but a personal matter not to be profaned by politics.

FORBES: Separation Of Church And State Limits Neither Churches Nor States

Perhaps we should say it this way: the purpose is a personal matter, sir, of yours.

NEWYORKER: Heirs

In any case, as I mentioned, this is definitely not just a personal matter of ours.

NEWYORKER: Heirs