Nested json array using jsonconvert.serialize() issue

[jack.chan]

i require the following json format

 "value": 
    {
      "user": [
        {
          "id": "123123",
          "value": "jerry"
        }
      ],
      "manager": [
        {
          "id": "234234",
          "value": "ENG"
        }
      ],
      "pinName": "PIN11111"
    }
  ,
  "itemConfigId": "itemConfig#123"
}

However when i use jsonconvert.serialize() (on my datatable in datatable), it treats the output as an array (see below)

To convert it to the above format i can just remove the outer square brackets [ ] but have difficulty removing the inner square brackets. Is there any way using json.serialize() (or other tools/method) to output a json with the above format???

[{
  "value": [
    {
      "user": [
        {
          "id": "123123",
          "value": "jerry"
        }
      ],
      "manager": [
        {
          "id": "234234",
          "value": "ENG"
        }
      ],
      "pinName": "PIN11111"
    }]
  ,
  "itemConfigId": "itemConfig#123"
}
]

i highlighted all the square brackets that should be removed

[ppr (Peter)]

whats exact input?
whats is the exact requirement / expected result?