To be tip for English natives
In Portuguese the verb to be has two translations: Ser and Estar. The fundamental difference between them is that Ser = definition, i.e. permanent state. When Estar = temporarily state (even if this "temporarily" is undefined). For example: "Ela deve estar doente" best translation would be "She must be sick" since sickness is presumably a temporarily state. "Ser ou não ser" would become "To be or not to be" since who you're is permanent (avoiding philosophical discussions).