Getting only one line i.e Configure Successfully message in postman in json but when added in json file for asserting its taking as invalid

So I got a response from the API, configure Successfully (like this only with no quotations or flower brackets) in JSON format in Postman.

I want to assert this in REST Assured, using a JSON file, but its telling its a invalid format , I have tried multiple String to JSON formatters, but all give the same invalid response.

And when asserted, the test fails.