Love status

In my previous job I liked my female supervisor, I reported directly to her. And very first day I love her a lot, But don't know She loves me or not. Whenever I tried to start her marriage topic with another she always denied and 3 times I asked her that she could be my younger sister but she never replied me properly, I did this only for check her feeling about mine.

Now I worked at another company and she is still there, I want to propose but don't know she loves me or not.