How to permanently delete POP3 e-mails?

Hello, my first day to the website. I am looking for some way of permanently deleting an e-mail message that is currently in my outlook. Outlook is configured in a POP3 config. No exchange server. I know u can corrupt the PST file and recover deleted messages so i need some way to ensure no one will ever recover this e-mail. Since i still didn?t delete it i was thinking of editing and saving it few times. Will it be possible to identify various changes to a specific e-mail.. (to see if content been changed.)? But the ideal scenario would be to permanently delete it..? any software out there?

Thank you for any info

Appreciate it