Why this girl is giving me mixed signals?

We work for the same company but we seldom see each other. Like once a month. We hardly had any small talk, a couple of hi's and hellos but definitely there are sparks. We stare and smile at each other a lot. But whenever i email or text or call her, she is not interested. So when i got to see her again, she stares at me and smiles and blurts out something in chinese. Yup she's chinese.