Remove extra \ (backslash) after json serialize string which convert from datatable to json without replace

When I convert a datatable to a json string in .NET Core:

JsonConvert.SerializeObject(result)

I get an output like 1

In Datatable records, also in Json format:

enter image description here

After merging all column values, code side in single that time happens this things

Please help me to remove backslash without using replace method.