a) either simulate 'pretend' versions of the beliefs, desires, character traits and context of the other and see what emotional feelings this leads to;
b) or simulate the emotional feeling and then look around for a suitable reason for this to fit. Either way, full empathetic engagement is supposed to help to understand and anticipate the behavior of the other.
Empathy may be painful to oneself: seeing the pain of others, especially as broadcasted by mass media, can cause one temporary or permanent clinical depression; a phenomenon which is sometimes called weltschmerz.
Without a basic emotional understanding of others there is no basis for relationship, therefore a tension struggle lies in the dilemma to protect oneself from the pain of empathy or seek to relate to other humans despite the potential risk of injury.