Complex sentence: Roy (played by Abhishek Bachchan) is a professional conman, who is a master of his dubious "art.", duping everyone including his honest and true girlfriend Simran aka Simi (Priyanka Chopra).
Split into simpler sentences: Roy (played by Abhishek Bachchan) is a conman, a master of his dubious "art.". He dupes everyone including his honest and true girlfriend Simran aka Simi (Priyanka Chopra).