UnityWebRequest

I've been trying to deal with a simple POST webrequest for 3 weeks and have now come to a standstill. I can successfully send a request to generate a new wallet address and privateKey but that endpoint takes no parameters. I use the same api https://api.shasta.trongrid.io/transferassetprivatekey{pk,to_address,asset_Id,amount} obviously containg thae values in hexString hexString 2 ints.The user must only input pk. So I tryed C#2json to no luck.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;
using System;
using UnityEngine.UI;
public class TransferAsset : MonoBehaviour{
/*create,sign broadcast
*
* curl -X POST https://api.trongrid.io/wallet/transferasset -d '{"privateKey":"users", "to_address": "41e552f6487585c2b58bc2c9bb4492bc1f17132cd0", "asset_Id": "1002169", "amount": 10}'
*
*/
string owner_address;
public InputField ownersAddress;
// Start is called before the first frame update
void Start()
{
privateKey = GetComponent<InputField>().text;
}
IEnumerator CreateTransaction()
{
UnityWebRequest request = new UnityWebRequest("http://api.trongrid.io/wallet/easytransferassetbyprivate");
string json;
json = "{\"owner_address\":\"41d1e7a6bc354106cb410e65ff8b181c600ff14292\", \"to_address\": \"41e552f6487585c2b58bc2c9bb4492bc1f17132cd0\", \"asset_name\": \"31303030303031\", \"amount\": 100}";
jsonToSend = JsonUtility.ToJson(json);
byte[] jsonToSend = new System.Text.UTF8Encoding().GetBytes(json);
request.uploadHandler = (UploadHandler)new UploadHandlerRaw(jsonToSend);
request.SetRequestHeader("Content-Type", "application/json");
request.downloadHandler = new DownloadHandlerBuffer();
yield return request.SendWebRequest();
if (request.isNetworkError){
Debug.Log(request.error);
}
else
{
Debug.Log(request.downloadHandler.text);
byte[] results = request.downloadHandler.data;
if (request.isDone)
{
Sign();//another ienum