This area of verbs of changes is quite a complex one. Other European languages use one verb to express the change of an object or a subject. Neither English nor Spanish is one of those. Mostly those verbs are translated with get, become, turn.

English	French	Italian	Spanish
He turns crazy. He becomes a doctor. He gets nervous. A man can turn into a woman.	Il devient fou Il devient medecin Il devient nerveux Un homme peut devenir une femme.	Lui diventa pazzo Lui diventa medico Lui diventa nervioso Un uomo púo diventare una donna.	Se vuelve loco Se hace médico Se pone nervioso Un hombre puede convertirse en una mujer.

Unfortunately it is hard to get a translation 1:1 and therefore we'll have look at the system in Spanish. As we see to turn (into) something can be hacerse or convertirse. The Spanish language takes here into account how voluntarily the change happened or whether something happened to the object without the object wanting or sometimes even knowing it.

Further we can see that even though French, Italian and Spanish are in the same family of languages the, Roman ones, they do not function the same way.

The following table tries to run all the verbs of change into a system to ease the answer to the question which one should be used when.