pertaining to · concerning · with regard to · about · a matter of

I can describe China, especially in relation to big cities like Beijing, in one sentence - China is a country whose pace of life is both fast and leisurely.

Concerning this matter... I really don’t know.

If there are genuine differences between these two cultures, I think that the largest are certainly in what you think about foreigners studying your native language.

With respect to financial matters, Mr Jones knows more than anyone else in the company.

When using this information, I will follow any conditions you specify, whether that's anonymity or giving detailed reference.