Complex sentence: Blue informs Babydoll that her virginity will be sold to a client known as "The High Roller" (Jon Hamm), who is actually the doctor scheduled to perform the lobotomy.
Split into simpler sentences: Blue informs Babydoll that her virginity will be sold to a client known as "The High Roller" (Jon Hamm). The "High Roller" is actually the doctor scheduled to perform the lobotomy.