For evidence, Juliet said "And Tybalt’s dead, that would have slain my husband All this is comfort; wherefore weep I then?" This is meaning that she is a ease about the situation and she understands that Romeo killed Tybalt for a reason and it is all not so bad. But at first she said "O God! Did Romeo’s hand shed Tybalt’s blood?" this basically shows that she was shocked or worried because of the "O God!" and she was thinking as if Romeo did something extremely bad or terrible.