There are different words used to convey feelings. Although the words empathize and sympathize are similar, they are still very different.
The word empathy means to feel and understand what another person is feeling. Sympathy is often used to convey a feeling of sorrow, without necessarily relating, for what another person is feeling or going through. To empathize with someone means .
that one can imagine themselves in the shoes of another and relate to how it feels to be in that certain situation. Sympathy is different because one does not necessarily have to relate to the situation at hand. One can feel sympathy without ever having gone through that particular situation.
The main difference in knowing when to use empathize versus sympathize is in relation to the situation. If one can interchange themselves with another and associate with the feelings of that person then the word empathy or empathize should be used.
More Reference Links: http://grammarist.com/usage/empathy-sympathy/ http://www.afterpsychotherapy.com/empathy-vs-sympathy/