我要他好看 The meaning is opposite. Actually it means 我要他不好看。 "I will make him lose face"

这是说反话。（故意反过来说）。在口语里这个说法相当普遍。例如： “我要让他（给他）好看！” “有你（他）好看的！” 但加上“觉得”，一般就只会被理解为正面的原意了。例如：“我要让他觉得好看”，“这让我觉得好看”这两个句子，不会被理解为“令。。。难堪/出丑”的意思。

I would like to suggest you understand this sentence in this way. 我要让你好看I'll make you To be looked Funny by others.

好看 的意思一般是看起来美观、体面的意思。它的另外的意思就是使人难堪、窘迫、尴尬等等意思，好看 在此其实是反语 （反语是一种修辞的手法，即用相反的词语表达意思）所以，好看 此处真正的含义是使人不好看，难堪，没面子。 比如：注意点吧，别再伤人自尊了，不然以后有你好看的。 Could I say something like "这让我好看” ( This embarrassed me) or "这让我觉得好看“( This made me feel embarrassed)? 这让我好看，要根据上下文的意思，比如，当着大家的面，他这样说话，不是让我好看吗！如果这样说，略施粉黛，这会让我好看点。就是另外的意思了。一般，在说自己时候，常常会说，这让我挺尴尬的，or使我挺没面子的。

好看 means look good/nice/beautiful in fact, this word has just this meaning, so even if in this sentense: 我要他好看, the 好看 means look good too. but here, it is a kind of irony. 我要他好看 means I make him to look good. which means I want to make him not to look good-----embarrass him. for example, ur friend do something very stupid. u can say: u r so so so smart!, in fact u want to express that "u r so so so stupid".