I saw the following example sentence in a dictionary:

> 
> It would ease my mind to know you had arrived safely.
> 
> 
> ([Longman Dictionary](http://www.ldoceonline.com/dictionary/ease-somebody-s-mind)) 
> 
> 
> 

I'm curious about what the context could be, and why the past perfect is used. There is no simple past tense to act as an anchor for the past perfect.

The following is a brief dialogue. Do you think the sentence is correctly used here?

> 
> Mary: Why do you want me to give you a call when I arrive in Paris?
> 
> 
> John: It would ease my mind to know you **had arrived** safely.
> 
> 
>