Complex sentence: Buck immediately recognizes that Bug's only interest in Tia is for sex and warns his niece, who refuses to listen, instead doing all that she can to try and make Buck's life miserable.
Split into simpler sentences: Buck immediately recognizes that Bug's only interest in Tia is for sex. He warns his niece about this but she refuses to listen, instead doing all that she can to try and make Buck's life miserable.