However, if the message is truly gone forever, there is little hope of recovering it. When in these email purgatory folders, it’s very easy to recover a “deleted” email. Only after deleting an item from these temporary folders, or after a certain amount of time has passed, is your email truly gone forever. Similarly, when you delete a message in Outlook, it goes to a folder called “Deleted Items” or “Trash”.
How to Recover Deleted Emails From Gmail.