Marco promises him that Eren loves him too. But Marco was too nice for his own good and would lie to keep his feelings from being hurt, and that Marco believed in the best of people. Jean knew that. And that's why it hurt so much. Alternate summary- In which Jean has a lot of tattoos, Eren has to get over himself, and Marco really just wants them all to just get along. (Not as lame as it sounds (I hope :d). Also it ends happily. So yay? Terrible at summaries)