Can I use xbehave.net with isolation (faking mocking substitution) libraries?

Of course!

You can use any isolation library you like with xBehave.net.

Our recommendation is FakeItEasy.

E.g.

using FakeItEasy;

public class CandyShopFeature
{
    [Scenario]
    public void BuyingCandy(ICandy lollipop, ICandyShop shop, SweetTooth developer)
    {
        "Given a shop with a top selling candy"
            .x(() =>
            {
                lollipop = A.Fake<ICandy>();
                shop = A.Fake<ICandyShop>();
                A.CallTo(() => shop.GetTopSellingCandy()).Returns(lollipop);
            });

        "And a sweet tooth developer"
            .x(() => developer = new SweetTooth());

        "When the developer buys the tastiest candy from the shop"
            .x(() => developer.BuyTastiestCandy(shop));

        "Then the developer should have bought the top selling candy"
            .x(() => A.CallTo(() => shop.BuyCandy(lollipop)).MustHaveHappened());
    }
}