Complex sentence: Kaori met Kōsei when she asked Tsubaki to set her up with Watari, and eventually convinced Kōsei to play the piano again, first as her accompanist and later in a piano competition.
Split into simpler sentences: Kaori met Kōsei when she requested Tsubaki to set her up with Watari. Kaori eventually convinced Kōsei to play the piano again, first as her accompanist and later in a piano competition.