"empathising" is to relate to someone's feelings or emotions, to feel the way that they feel. It has nothing to do with "emphasising" anything. You can only "empathise" with a person's feelings or emotions, while you can "understand" anything.
For example, you can empathise with someone who's failed an exam, or you can empathise with their desire to move to another house if they don't get on with their parents. You can understand their feelings, but you can also understand a book or a novel or a policy. You can't "empathise" with a policy if there are no emotions involved. I hope this helps!