Not the Reaction I was Expecting

I gave the gift to someone today from my last travel and I didn't get the reaction I wanted. Maybe I was just expecting too much. She doesn't believe what I say to her although I've was not kidding around when I was talking or having a conversation with her. I don'r know if the term is right but I can perceive that she thinks of a me as a "joke" because she's always thinking that I was joking around. Why is that? Or maybe she just want don't want to acknowledge what I'm saying. I can only guess and my guess is a depressing one.