I have posted an answer and not only have gotten -1 votes for it, but also a delete (1). How can I view the delete (1) reason? I'd like to fix it.
Perhaps you are thinking that, in analogy to "closure reasons", there are also "deletion reasons". However, this is not the case - nothing in the Stack Exchange software asks for any reason to be given for a delete vote.
Of course, when someone casts a vote to delete, they have the option of explaining their reasons in a comment. You can ask for such an explanation via a comment of your own on the post. But unless, and until, the post is actually deleted, there really isn't anything you need to do, or can do; in particular, your meta post here is unnecessary. The software won't reveal who cast the delete votes until the deletion actually takes place (the threshold is 3 votes). If this becomes a pattern, i.e. you believe that someone is maliciously casting delete votes on your posts, then flag a moderator.