I think a way to go and maybe sell even better is to go snarky or a little bit against the Valentines Day grain. Not hateful, but tweak it a bit. I’m thinking of the coffee mug a co-worker has that says, “Have a happy whatever doesn’t offend you.”
So I’m picturing a heart or flower or whatever that says something like, “This hereby certifies my acknowledgement of this and all future Saint Valentine’s Days.”