Regex to replace password

test.cs

using NUnit.Framework;

namespace REGEX.TESTS
{
  [TestFixture]
  public class RegexTests
  {

    [Test]
    public void Regex()
    {
      var requestBodyJson = "{\"Username\":\"Tom\",\"Password\"}";
      var test = Regex.Replace(requestBodyJson, "\"Password\":\"[^\"]*\"", "\"Password\":\"*******\"");
     Assert.IsTrue(test.Contains("\"Password\":\"***\""));

    }
  }
}