Get JSON data from raw String/HTML - ios

Question

There is a div on UIWebView which is hidden and on DIV, there is some kind of string which also contains some JSON response as well.
NSString *response = [webView stringByEvaluatingJavaScriptFromString:#"document.getElementById('response').textContent"];
There is JSON response start with the key "FinalizeResult"
and the response string is
response = Illuminate\Http\JsonResponse Object
(
[jsonOptions:protected] => 0
[data:protected] => {"FinalizeResult":{"ResponseCode":0,"ResponseDescription":"Request processed successfully","UniqueID":"18278712782","version":"2.0","Account":"MyAcount","Amount":"102.000","ApprovalCode":"21782","Balance":"102.000","CardBrand":"Visa","CardNumber":"411111******1111","CardToken":"21212122121","Fees":"0","OrderID":"166221"}}
[callback:protected] =>
[encodingOptions:protected] => 15
[headers] => Symfony\Component\HttpFoundation\ResponseHeaderBag Object
(
[computedCacheControl:protected] => Array
(
[no-cache] => 1
)
[cookies:protected] => Array
(
)
[headerNames:protected] => Array
(
[cache-control] => Cache-Control
[date] => Date
[content-type] => Content-Type
)
[headers:protected] => Array
(
[cache-control] => Array
(
[0] => no-cache
)
[date] => Array
(
[0] => Mon, 04 Dec 2017 10:30:52 GMT
)
[content-type] => Array
(
[0] => application/json
)
)
[cacheControl:protected] => Array
(
)
)
)
How can we get this JSON response?