after Newtonsoft.Json.JsonConvert.SerializeObject

{
   "?xml": {
      "@version": "1.0",
      "@encoding": "UTF-8"
   },
   "RootDTO": {
      "destination": {
         "name": "companyName"
      },
      "orderData": {
         "amount": "123.45",
         "items": {
            "element": {
               "binding": "saddle",
               "components": {
                  "element": {
                     "width": "210"
                  }
               },
               "description": "Introductory x"
            }
         }
      }
   }
}