When "desempeñas" is used, it refers to the actions of an individual in the present tense. For example, "Tú desempeñas un papel importante en este proyecto" means "You play an important role in this project." Similarly, "Desempeñas tus tareas con diligencia" translates to "You carry out your tasks diligently." The specific nuance of the translation depends heavily on the object or the situation described.
The verb can also be used in phrases that indicate the fulfillment of an obligation or the execution of a function. For instance, "desempeñar un cargo" means to hold or occupy a position, and therefore, "tú desempeñas un cargo" would mean "you hold a position." The concept of performance or execution is central to the meaning of "desempeñar" and, consequently, its conjugation "desempeñas."