彼の落ち着いた態度に私の恐怖心は消えた。
My fear disappeared thanks to his relaxed disposition. (given translation by duolingo)
The usage of に is confusing me in this sentence. I would be happy with 態度のために or 態度のおかげで, but に on its own is not something I've seen used like this before.
Is this good grammar? Is it maybe more/less formal than the other two options? In what situations should I use に like this?
