We aren’t specifically told why Jesus wept at Lazarus’ tomb. A possible answer is that he was upset because his friend was dead (although he knows he’s going to raise him soon [John 11:23], so this doesn’t seem like the fullest answer). Another possibility is that he weeps because the people around him don’t seem to recognise that he has the power to be able to raise the dead (i.e., he weeps because of their unbelief; cf. Luke 19:41-42). Or another possibility is that Jesus weeps because he’s so sad about the sad state of the world that was once created so beautifully, a world where people sin and death is so prevalent. Or potentially the fullest answer could be a combination of things like these.