That's a way to put it. Let's hope Seranimo isn't a Christian, though, because in Christian Latin it would be interpreted a little differently — in a way that might make a Christian worried for their soul.
In Christian Latin, paenitentia refers chiefly to repentance or penance for one's sins. You had a chance to repent as long as you were alive. If you died unrepentant, however, you were doomed to hell.
Since "regret" is said to come from the Old French regreter, "bewail (the dead)," one might use a form of maereo, "grieve, lament, bewail, mourn over."