True Ability, True Power
The truth behind someone's strength is their true strength. It is also their true ability.
This is a jukugo word, which usually means on'yomi readings from the kanji. Since 力 has two on'yomi readings, here's a mnemonic to help you remember which one to use:
Your true strength is sealed behind two locks. Gee, two locks (じつりょく)?! People must have been scared of your true power to seal it behind two locks!
Even if I used all of my true strength, it was still a draw.
The younger brother seems to be worried about why he cannot be a professional, despite his true strength.
Koichi's hula dancing abilities are genuine.