"diligence in" is a correct and usable part of a sentence in written English.
For example, you could say: "He was praised for his diligence in completing the project on time."
Due diligence in collecting information is essential.
Due diligence in the service of justifying a paycheck.
Financiers are sometimes skimping on due diligence in the scramble to win deals.
"We continue our diligence in keeping our force protection at appropriate levels".
That isn't exactly journalistic due diligence in a case where such extreme allegations are being made.
Hunter spent $80,000 in due diligence in 2008 before dropping the matter.
In addition, traditions supported 30% down payments, and due diligence in mortgage originations.
"I would also like to thank the jury for their diligence in reaching their verdict.
From this Instance, Reader, Be encouraged to Diligence in thy Calling.
He thanked border force staff for their "diligence" in detecting the "illegal arrival" at the border.
However, we would like to thank the independent QC for his diligence in reviewing this decision.
