美国喜剧《亿万未婚夫》中台词still sees what you think you look like.语法是否有错，该怎么分析！

still sees what you think you look like没有语法问题。
主语共用前面的someone,将语序调整一下就OK了：
It's a wonderful thing,as time goes by,to be with someone who looks into your face and still sees what you think you look like，when you've gotten old.

其中what you think you look like作see的宾语，如果是单独的问句就是这样的语序：what do you think you look like? 常见吧？！

sees what you think,what you look like.
省略了 ,what因为重复,所以省略

语法没错。somebody (still) sees sth.
这儿的sth= what you think you look like. － 表示你自认为你看上去怎样。

你把句子的主干提出来看就简单多了。 我的翻译是： “当时光流逝，当你已然老去时，有这样一个人 － 当他／她看着你的脸， 却仍然觉得你很年轻 － 这是多么奇妙而美好的事！～”