I'm not sure why people complicate things: this is how you fetch email body with MailCore2:
MCOIMAPSession *session = [[MCOIMAPSession alloc] init];
[session setHostname:@"imap.gmail.com"];
[session setPort:993];
[session setUsername:[UICKeyChainStore stringForKey:@"username"]];
[session setPassword:[UICKeyChainStore stringForKey:@"password"]];
[session setConnectionType:MCOConnectionTypeTLS];
MCOIMAPFetchContentOperation *operation = [session fetchMessageByUIDOperationWithFolder:@"INBOX" uid:message.uid];
[operation start:^(NSError *error, NSData *data) {
MCOMessageParser *messageParser = [[MCOMessageParser alloc] initWithData:data];
NSString *msgHTMLBody = [messageParser htmlBodyRendering];
[webView loadHTMLString:msgHTMLBody baseURL:nil];
}];