Complex sentence: Upon his return, the student describes the dance and the dancer so vividly that his betrothed concludes he has been unfaithful; the opera ends with a funeral procession for the student's fiancée (the letter is unclear as to her cause of death).
Split into simpler sentences: Upon his return, the student describes the dancer in great detail, causing his betrothed to suspect he has been unfaithful. The opera ends with a funeral procession for the student's fiancée (the letter is unclear as to the cause of death).