The first two words that you see on the email that the editor of an academic journal send you after you submitted a paper to them usually half a year ago.
With regret, I must inform you that, based on the advice received, the Editors have decided that your manuscript cannot be accepted for publication in the Journal of Dipshit.
On invitations, it is the opposite of R.S.V.P.
. People must call if they cannot attend, rather than R.S.V.P.-ing.
Girl: Hey, I read your invitation, and I noticed it said "with regrets", so I just called to say I will not be able to attend your party. Sorry!