Ehm... you could submit email to an smtp relay using SSL, but that does NOT IN ANY WAY tell you what's happening afterwards. This smtp relay will probably forward the email to another smtp server without using transport-encryption, and this will forward the mesage to another, etc... The end-user will use IMAP or even POP3 without transport-encryption to fetch the message, etc. etc.
If you're handling sensitive data, just don't ever use email to transport it.
The email module on the AppStore supports SSL email servers.