Dear singlag,Brother,I think she has been giving these subtle hints that she has interest in you to at least certain extent ,otherwise women are far more aware of the effect than us can think about their attire is having ! And particularly they are too careful and ensure that they are not exposing their vital body parts to any male! But here Even after catching you directly staring at her clevage and after your apology says ok and smiles ! I will at least take this as her inteest in you! and she has been expecting you to make some move! But as you both working in same organisation and you being her senior and if her intentions are at all bad she could accuse you of sexual harrasment too! So better ensure that her feelings are genuine !For that you have to run a check on her social,educational ,family background! Upon you being satisfied with that you can think of expressing your love to her ! For that rather than ogling her body start to look into her eyes directly as long as possible and also start to praise her on her looks and the way she carries herself and the way she dresses and color combinations she uses and like this! She will obviously reciprocate appropriately then one day tell her about your feelings to her and i am sure she wont turn down your proposal!