What does it mean when like a girl ask you serious questions or says something serious but then laughs? Like?

when it was my vacation in texas an i was leaving the girl was like "No Jared you can't leave me; haha" She always laughs at the beginning or end of a what i thik to be serious comment or question like "you should txt me an let me know how your vacation is going; hahaha" Does this "Merry Christmas jared i miss you alot. Haha" Idk why she does that??