Pork is inherently sweet, a characteristic intensified by roasting. Cream is faintly sweet, also. An off-dry white wine is the ideal partner for this combination, particularly if the wine has a nice counterbalance of acidity, which matches the tartness of the mustard and carries just a hint of herbal flavor to echo the tarragon. Accompany the pork loin with sauteed apples and fried or roasted potatoes. Dependable: off-dry American Riesling. Daring: medium-bodied Merlot.