I think I understood your question correctly now. As I understand, you are writing an application to send mail. And in your application, whenever you send a mail, you also want verify that if mail was delivered and also if it was not delivered then you want to get hold of the failure message in your application. Is that how you mean?
Well, if that is how you mean, then I think it is impossible to track the mail status with your apllication code. For instance if you are using java sendMail in your apllication you can only ensure that the send happened from your code successfully(without any send exceptions like java.net.SocketException or javax.mail.MessagingException). But, you can never ensure if the mail really reached the recepient. i.e. you can never track in your application if the mail was rejected due to wrong recepient address or any other error like illegal attachment at receipient mail server or errors like blocked sender id etc.
That is because any such error condition will be communicated by the receipient mail server to the sending mail server the information of which is present in the sent mail's header.
Does that answer your question? (Or did I understand your question correctly? ;-))