my girlfriend slapped my in the face outside a club and a police officer saw this. he arrested her even though i repeatedly said i didn't want to press charges. should i go to court with her? how should she plea?
The state is prosecuting your girlfriend despite your objections because she committed an offense against the state (by violating the law).
If your girlfriend had been to court, there may be an order against her from having any contact with you. If there is an order prohibiting her from contacting you, she can be in additional troubles if you contact her and she continues the contact.
How she should plea is a matter between her and her attorney. If she is indigent according to local standards, she is entitled to free representation by a public defender. She always have the option of hiring a private attorney.
If you want to help her, you should review the facts with your own attorney to see what you can or should do. If you are subpoenaed to appear in court to testify, you likely must appear. However, you may be able to assert certain rights that may limit your testimony.