Are you referring to GMail? -> G-mail deletions

With most email services there will be a trash or deleted items folder you can check to see if the items have been sent there. Generally after 7 days they are auto-deleted from that Deleted items folder (many but not all email services do this.) If you are in the Deleted items folder you can instead re-select the emails and choose delete which will delete them forever. Or there will be a button that will delete all items in that folder immediately or two buttons: one to select 'all' and second to 'delete'.

I'm wondering if you are becoming confused between the Inbox and Deleted items folders.