var datastring = {
        newEmailForm: newEmailForm,
        properties: properties
    };

    //got the data, make the ajax request
    jQuery(function(){
        jQuery.ajax({
            type:'POST',
            data:{
                action: 'elegantSendEmail',
                datastring: datastring
            },
            url: ajaxurl
        })
    })

action  elegantSendEmail
  datastring[newEmailForm][0][] {…}
    0   email
    1   title
    2   Message
  datastring[properties][0][]   {…}
    0   31466
    1   value1
    2   value1
  datastring[properties][1][]   {…}
    0   31440
    1   value2
    2   value2

$obj = json_decode($_POST['newEmailForm'][0], true);

echo '<pre>';
print_r($obj);
echo '</pre>';

$obj = json_decode($_POST['datastring']['newEmailForm'][0], true);