Is the revocable return (rajʿah) valid if it occurs without witnesses, and what is the ruling on a divorce pronounced by the husband while ignorant of its occurrence?

Your returning to your wife is valid as long as you took her back during her 'iddah (waiting period), and your not having witnesses for it does not prevent its validity. And whoever utters a clear divorce, their divorce takes effect, whether they were alone or others heard it, and whether they knew the ruling of divorce taking effect by their clear utterance or were ignorant of it.