Who is Ruth Rassmussen from In the Lake of the Woods and what is their importance?

Ruth Rassmussen is the wife of Claude. Ruth is a down-to-earth woman who continually says that there is no reason to believe that John had anything to do with Kathy's disappearance. Ruth says that she believes that sooner or later she will get a note in the mail indicating that John and Kathy are alive and well somewhere. She says that they have a deep abiding love and compares that to the love she shared with Claude.