Reassurance Corrections

Letter Format

Grammar = Social Standard

People care about the rules they believe exist, and the usage they deem to be correct.

Word choice: insure more common than ensure in general writing; in business writing, legal issues. Assure always come with who is being assured-- "I assure you that I will eat the cake." Ensure/insure generally interchangable, but not with business writing.

Ordinals and Cardinals

Websters
Again
More on ordinals
According to Sabin, you can use ordinal figures (1st, 2d, 3d, 4th, etc.) or ordinal words (the first, the twelfth, the thirtieth, etc.) when the day precedes the month or stands alone (as it does in "the 13th of November, 2001" or "Tuesday, the 13th"). In the typical American format . November 13, 2001 . we would not use ordinal designation even though you might add that "-th" when you say the date out loud. Sabin also recommends that we avoid the form "the sixth of March, 2003."

Active instead of Passive

Active: Our accounts payable department will pay the invoice in two weeks.
Passive: The invoice will be paid in two weeks by our accounts payable department.