Complex sentence: Shortly after his arrival in Italy, Ripley concocts an accidental meeting on the beach with Dickie and his fiancée, Marge Sherwood, and quickly insinuates himself into their lives under the pretext of being a fellow jazz lover.
Split into simpler sentences: Shortly after his arrival in Italy, Ripley concocts an accidental meeting on the beach with Dickie and his fiancée, Marge Sherwood. However, Ripley quickly insinuates himself into Dickie's life under the pretext of being a fellow jazz lover.