Usage of s’avérer

Question

There are two examples of the verb, s'avérer, in this exercise:

1) Et les compétences que j'ai acquises comme avocate se sont avérées inestimables dans ce nouveau domaine.

2) Ce changement se sera avéré être la meilleure chose que tu aies jamais faite.

My dictionary translates s'avérer as "prove to be" or "turn out to be". In the second example, the infinitive être is added to s'avérer whereas in the first it is absent. Is être optional? If the 'to be' is included in the definition, why is être necessary in the second example?

Céline Pickard · Accepted Answer

Bonjour Frank,
In 1), "s'avérer" can be directly followed by an adjective:
Les analyses sanguines ne se sont pas avérées concluantes = The blood tests were inconclusive
Les démarches administratives se sont avérées inutiles = The administrative procedure proved unnecessary
-> s'avérer + [adjective]
 However, in 2) "être" is required to introduce the noun phrase (la meilleure chose)
Ton camp s'est avéré être celui des perdants = Your side turned out to be the losing one
Le banquier s'est avéré devoir de l'argent à la mafia = The banker turned out to owe money to the mafia
-> s'avérer + [infinitive verb] + [noun phrase]
I hope this is helpful.
Bonne journée !

Jim Jones · Answer

Bonjour Frank,1) And the skills I acquired as a solicitor have proved invaluable in this new field.2) This change will turn out to be the best thing you ever did.The translations shown above demonstrate that only item 2) contains the text "to be" I see this as being the reason why the use of être is particular only in 2)There is no need for 1) according to the sentence structure in that case.I hope this helps.Bonne journéeJim