Each jingly site has a corresponding email address assign to it. Say, if your site address is sincere.ly/xxx, then the email address will be email@example.com.
Any premium customer, once paid for the service, can enjoy email forwarding to any email address.
This can be easily configured by going to:
Premium > Email
in the admin area of the site.
If one wants to disable the email forwarding, then setting an empty string will erase the forward.
N.B. target email address has to be a valid one. The system will check whether the target address can potentially receive emails.