Good friends would kiss each other on the cheek, but a disciple would probably kiss his master on the hand to show respect. No one knows for sure how Judas kissed Jesus. (See: [[rc://en/ta/man/translate/figs-explicit]])
This could mean ‘are you really going to betray me with a kiss?’ Jesus is not looking for an answer to this question, so some languages would translate it as a statement, such as: “you are betraying me by kissing me!” or “you make your betrayal even worse by kissing me!” (See: [[rc://en/ta/man/translate/figs-rquestion]])