Is he interested or just teasing?

he is our UPS guy and when he comes in he always seeks me out. He will ask me probing questions about where i have been when i haven't been at work or why i am sad. he said something about why no one brings me flowers and then stood at my desk and asked me point blank if i liked him because my key chain says "i have multiple personalities and none of them like you" he always calls me by my first name but does not personally address anyone else. I have done nothing ever to show any interest other than smile at him once in a while like any other vendor. I find him incredibly y with that bald head of his but he wears a ring on the wrong hand and i don't want to give anything away by asking if he is married. when he asked if i liked him i said the jury is still out because he put me on the spot. Should i flirt back?