The proper wording for an RSVP is either "Accepts with Pleasure" or "Regretfully Declines," according to About.com. These short phrases show both compassion and appreciation of the invitation. A challenge is presented for some to decline an RSVP in a nice way.
About.com reports that proper wordings for RSVP are becoming less formal. As society continues to grow and accept more creativity, wording for RSVPs should favor the audience that sent out the RSVP. However, About.com advises that certain measures that show compassion and appreciation should still be taken. The most important aspect of wording an RSVP is to know the audience and respond respectfully.