Fake a method on an object

Hi all,

what I would like to do is that a method of any object returns always true, like in this this minimal code :

public class MyClass
{
    public bool Verify()
    {
        MyClass2 myClass2 = new MyClass2();
        return myClass2.Check();
    }
}

public interface IMyInterface
{
    bool Check();
}

public class MyClass2 : IMyInterface
{
    public bool Check()
    {
        return false;
    }
}

class Program
{
    static void Main()
    {
        var fake = Isolate.Fake.Instance<IMyInterface>();
        Isolate.WhenCalled(() => fake.Check()).WillReturn(true);

        MyClass myClass = new MyClass();
        // I would like that Verify() returns true everytime, so how could I fake the Check() method to return always true ?
        Assert.AreEqual(true, myClass.Verify());
    }
}

But this is not working.
I can't refactor the code to put a IMyInterface in the myclass constructor parameter (or as method parameter).

How should I do ?

Thanks for your help,
Best regards

Edit : I tryed this too :

var fake = Isolate.Fake.Instance<IMyInterface>();
Isolate.WhenCalled(() => fake.Check()).WillReturn(true);
Isolate.Swap.AllInstances<IMyInterface>().With(fake);

but this shouldn't be the good way