The good liar by Nicholas Searle (2015)
"Veteran con artist Roy spots an obvious easy mark when he meets Betty, a wealthy widow, online. In no time at all, he's moved into Betty's lovely cottage and is preparing to accompany her on a romantic trip to Europe. Betty's grandson disapproves of their blossoming relationship, but Roy is sure this scheme will be a success. He knows what he's doing" -- provided by publisher.