Due diligence and withstand meaning and use

can anyone explain me the meaning of the following words and how can it be used in a sentence.

1-due diligence

Check this out:

And regarding “withstand”, as far as I know it means to oppose with firm determination.

For example, an underwriter’s due diligence in the initial public offering context must withstand a greater degree of scrutiny than in other offerings.

Copy pasted from google :slight_smile: