And unless you can prove an illegal motive, you cannot sue, no matter how unjust or arbitrary your firing. In order to walk away with a successful wrongful termination investigation or lawsuit, you'll need to prove that the employer acted with an illegal motive.In many cases, the answer is yes. Before filing a claim in Arizona, you must determine if your termination was wrongful. How To Sue For Wrongful Termination? If you think that your termination was unjust, it's important to understand the steps you should take to protect your rights. Settlements: To avoid the costs and uncertainties of litigation, employers may choose to settle wrongful termination claims out of court. To find out what your legal claims are, speak to an experienced Arizona employment lawyer. Need Professional Help? Enhances your chances of success in court. 3.