If you are asking for the possible penalties for assault in the fourth degree, RCW 9A.36.041 provides "(2) Assault in the fourth degree is a gross misdemeanor." The statutes are at http://apps.leg.wa.gov/RCW/default.aspx?cite=9A.36 .
In Washington State, a gross misdemeanor is punishable by up to 1 year in jail, a $5,000 fine, or both. What a defendant actually gets depends on the criminal history of the defendant. Most first-time offenders do not get the maximum penalties.
If you are charged by a city, it may have its own penalty schedule.
You likely should review your facts and options with an attorney.
The most likely issue for the defendant here will not be jail or the fine. Many of the courts impose anger management evaluations, alcohol evaluations, etc., depending on the facts of the case, as a condition of a supervised or court supervised probation.
Every case is different and the amount of jail time depends on the prior record.
The maximum penalty is 365 days in jail and a $5,000 fine. A conviction will also result in the loss of your right to possess a firearm, a no-contact order between you and the alleged victim, and DV Batterer's Treatment.
Get a good lawyer. Good Luck.