She is not a person to fear.
She is not a person to be feared.
It is fine to use both forms, but I cannot catch the definite difference between them in meaning. Also, why is it OK to use both forms? It seemed to me that when there is "noun+to phrase" structure, this to phrase is linked to the subject. For example:
We didn't have anything to wear. (Who had nothing to wear? Us!)
But unlike this example sentence, the to phrase in sentence 1 implies that I or we are the people who should not fear her, which means that it's not modifying its subject "her", but other nouns that are not even in the sentence. The sentence itself makes perfect sense to me, but I don't know why it is. Can someone please explain why it is grammatically fine to use sentence 1 and the difference in meaning between those two sentences?