I wish John (not be) busy tomorrow.

It sounds like you're trying to express a wish about John's schedule for tomorrow in Russian. In this case, you can use the subjunctive mood. The correct way to phrase your wish in Russian would be: "Я хочу, чтобы у Джона завтра не было дел." This translates to "I wish that John won't be busy tomorrow." Remember, in Russian, verbs in the subjunctive mood are often formed with the particle "бы" and the past tense form of the verb. If you have any more questions or need further clarification, feel free to ask!