Never imagine yourself not to be otherwise than what it might appear to others 【that】 what you were or might have been was not otherwise than what you had been would have appeared to them to be otherwise.
关键问题：黑框里的that是宾语从句的that还是主语从句的that。
追加问题：1.宾语从句that什么时候不能省略…（初中知识忘掉了）
2.有没有never...not 的否定否定等于否定的情况…（引文出处的上下文中有这样的表达情况。。。
感谢感谢…