Complex sentence: As the conversation goes on, it becomes clear that the young woman knows a great deal about Ike's family and his own life, more than Roth would probably have told her; she is part of the family herself, a distant Beauchamp cousin.
Split into simpler sentences: As the conversation goes on, it becomes clear that the young woman knows a great deal about Ike's family and his own life, more than Roth would probably have told her. For she is part of the family herself, a distant Beauchamp cousin.