Learn Farsi: در این بحران، ما باید خودمان را ارزیابی کنیم. - In this crisis, we must evaluate ourselves.

In this sentence, خودمان is the direct object of the verb — it is who we are evaluating. Because reflexive pronouns refer to specific, definite people or things, they require the definite direct object marker را when used as an object.

Could I move خودمان right after ما to make it ما خودمان باید?

You could, but it changes the meaning! If you say ما خودمان باید ارزیابی کنیم without را, the word خودمان becomes an emphatic subject. It would mean we ourselves must evaluate something else. In our sentence, خودمان را is a reflexive object, meaning we are evaluating ourselves.

Why does the verb ارزیابی کنیم not have the می prefix?

Because it follows باید. The word باید requires the next verb to be in the subjunctive mood. For the compound verb ارزیابی کردن, we drop the indicative می and conjugate the کردن part in the present subjunctive, giving us کنیم for the we form.

Does the ending on خودمان always have to match the subject?