Professor expressed interest in working together, is not responding to emails?
It's normal for professors to be extremely busy for an extended period, and not be able to respond to anything that requires significant thought or planning.  I would not say that she is "ignoring" your emails.

I would wait about a week from your last message, and then send one more message with a deadline.


  Dear Professor B,
  
  Just wanted to touch base again regarding my application and our discussion about working on Project X.  I am trying to make plans for the next few months, so if we are going to move ahead on this, I would need to know by date MM/DD.  I really hope it works out and look forward to hearing from you soon.


After that, do not send any further messages unless you get a substantive response from her.  If you don't get a response by the deadline, move on and look for other opportunities; either she isn't interested, or she hasn't been able to make time to evaluate your request, which would itself be an indication that she wouldn't be easy to work with.