There is no such functionality under the protocol SMTP
, the most approximate that you could achieve is to send an email where the person enters a link to verify that it arrived correctly, but it will be a manual operation.
It is the same thing that is implemented when you register in a site, which sends an email which when browsing confirms the registration.
It is not a limitation of the language, simply the mail protocol does not support this that you are looking to implement.
But an alternative could be:
Check if Email Address Really Exist or not Using C #
but here you would be running socket command against the smtp service to see if it responds with the existence of the mail, I have not tried it, but it could be an option.