How can I develop a working relationship with her where we communicate effectively? I don't want to be rude to her. – Lost in Translation, Seattle
A.: I am sure that your co-worker knows that she has an accent and that sometimes people do not understand her. But she may not realize to what extent you do not understand her.
Ask her to join you for a meeting, and be clear and direct with her. Tell her that sometimes you cannot understand her. Ask her if she would slow down when she is speaking to you to ensure that the two of you have accurate communication.
Check in with her as well to see if she understands everything that you are saying. She may be having a similar challenge, especially given that English is not her first language.
Pledge to work together to build effective communication. Chances are that she will appreciate your forthrightness.