how to check if a given email address actually exist in c#? -

I am creating a C # application where users create accounts and type their email address, I know How is it valid with regular expression, what I am doing is garbage with how to check that it is actually mail? I.e. lilush@gmail.com -> Is such an email address?

Thank you!

The only way to check is to send an email to that address and to make sure that you link to a link It is necessary to click on the account to activate the account. There is no other way to check that email is correct