I am confused about this sentence I found.
しかし彼が悪いヤツにはどうしても思えないのだ。
My take would be that に is used for an adverbial construction similar to "疑問に思う". So would "悪いヤツに思う" mean having a "bad-guy" feeling? Referring to this question asked before, you would use the を particle to mark the object you are having the feelings about, but it's が instead. Could に by itself encapsulate the whole phrase before it, i.e., "彼が悪いヤツ"? Or is there a part which is being omitted?
A good question. Actually the answer is, we never say 彼が悪いヤツに思う though we do say 彼が悪いヤツに思える. The construction rightly means "he seems a bad guy".
思える in this sentence is not the potential form of 思う, confusingly, it is another verb that describes perceptory appearance.
Similarly,
彼が悪いヤツに見える He looks like a bad guy
彼が悪いヤツに聞こえる It sounds like he is a bad guy
彼が悪いヤツに感じられる He is felt like a bad guy
It'd be ungrammatical if you swap the verb with 見る or 聞く, which takes senser as subject. Among them 感じられる is made from 感じる, which does not have an independent counterpart. This is done by a relatively rare grammar known as 自発 "spontaneous" -れる. You can also replace 思える in the first sentence with 思われる.
If you want to add information about senser in these kind of expression, such as "to me", the standard way is to put a 私には in the front.
私には彼が悪いヤツに思える
