My wife pointed out Grammarly to me, so I took a look at it.

Among other things, Grammarly checks for commonly misused words.
“The Grammarly editing tool not only helps you locate misspelled words in your writing, but also helps you to identify the correctly spelled words that you have used incorrectly.”
Grammarly requires credit card information in order to start the free trial, so I stopped my registration. I don’t like those sorts of trials- the ones that rely on the user to forget the trial was in progress.
Not long after, I got an email from Valerie Bass at Grammarly (see annotated screen capture below):

So I replied.
Hi Valerie-
Two things:
1. I don’t like “free” trials that depend on credit card info. They tend to rely on the user forgetting the trial is in progress.
2. Irony: You wrote:“Perhaps the requirement of a credit card or a PayPal account was a problem for you, in which case I’d like to ensure you that Grammarly will not charge you unless you choose to keep your subscription…”
I believe you meant “assure,” not “ensure.”
http://public.wsu.edu/~brians/errors/assure.htmlNo human at Grammarly proofed your email for correct use of words? I ran that sentence through Grammarly itself and noticed that it didn’t catch this mistake.
Best regards,
-David
