My best friend is hiding something from me?

She acts like nothings wrong, but i can tell when she phrases her words. I can tell somethings wrong. I Finley got her to say that there was something wrong but now she wont tell me. How can i help her if i don't know whats wrong? how can i tell her that i want to help her? iv already said "why are you embarred? jess were best friends we tell each Other these things" but shes only said that there are things on her mind that she would rather not tell anyone but her self. And that shes in no need of help. But she is!