It's not idfficult. Try it once at home without company to get it right. There are two areas where trouble can occur:
1. It's easy to overcook the magret. Time it carefully, and make adjustments after you do it once ore twice.
2. The sauce will separate if kept on high heat for much time after the bubbles become bigger. My best advice is to do the following: Prepare this dish as in the recipe, but leave some of the sauce in the pan and continue to cook over high heat til it separates, watching it carefully. Once you see what it looks like just before it separates, you won't do it again.