Generally if you appear to answer on the assault charge the state will move to dismiss the failure to appear. Cities file these charges so there is a record that you failed to appear in court, so later if you get charged with another offense they can easily see that you've already failed to appear in another case and perhaps a bond is necessary on the new case.
Attorney David Kephart is an experienced Criminal Defense Trial Attorney and Jury Consultant. He is the recipient of the Arizona Attorneys for Criminal Justice President's Award and the recipient of the International Academy of Trial Lawyers Commendation for Excellence in Trial Advocacy. His response to your question is intended to be a general statement of law, should not be relied upon as legal advice, does not create an attorney/client relationship, and does not create a right to continuing email exchanges.