En français : Il disait tenir le secret de religieux espagnols.
En anglais : He said to keep the secret of the spanish monks. -- Sorry, I don't have enough context here to work out whether this is about confession or not. Based on this, I would say that it is not, and I am unable to find any mention of "le secret" meaning confession in any of my dictionaries. It does seem to be referring to a particular secret, rather than just "secrets" or "confession" though. (Crédit : Sylang)