This will prevent Grace from sending you messages, friend request or from viewing your profile. They will not be notified. Comments on discussion boards from them will be hidden by default.
“Don't show a friend your gift, or your bag of money if you still want to maintain your relationship, but if nay, go on, and all you'll see is hate and jealousy, and you'll fight with him in the street like a dog and all you'll feel is regret.”
―
Michael Bassey Johnson