Capacidades could be translated equally as well in English in the singular. In other words: He tries to show his true capacity. In fact, the singular is better here. Capability could go either way.
Why does "verdadeiras" not come after "capacidades"?
When the adjective comes before, it usually takes a symbolic meaning. Verdadeiras in this context isnt simply the difference between true and false, but what the person really is deep inside, the inner person.
ah got it! Thanks.
"He tries to prove his true abilities."
Is that acceptable?
How to say "He tries demonstrating" ? Not "He tries to demonstrate".
Are "capacities" and "capabilities" the same in Portuguese?
Another answer Duo accepts is 'He tries to show his real abilities'. This version seems to sound more natural to an English speaker perhaps?
Yep.... we use capability as capableness