What does it take to understand grace? Nancy Seaman is a small lady, friendly and good-natured, known by her neighbors in their placid Detroit neighborhood as a dedicated stay-at-home mom. And she’s a murderer. In 2004 Nancy Seaman killed her husband, Bob. And the murder was assertive. Brutal. Seaman hit her husband with a hatchet and stabbed him with a knife more than twenty times in their suburban garage. Seaman readily admits to the grisly…