Salut, j ai besoin de traduir cette expression en Italien Tu peux le rendre souriant You can make him smile (en anglais)

I need somone to teache me japanese; somebody help me please :'-(

hello; I have some questions to ask, if can help me I'll be so glade ;-p I wanna know the meaning of "sempai"?; and what does it mean when we say the name of somebody than we say "sun" or "kun" ???