Your true colours
Definition 1 of 1
Pro Tip 1/3Emotional Revelation
The phrase often relates to revealing emotions or attitudes that were hidden before. 
At the competition, her true colours came through as she cheered for everyone.
Pro Tip 2/3Stressful Situations
People sometimes show their true colours in difficult or stressful situations. 
During the crisis, the leader showed his true colours by staying calm.
Pro Tip 3/3Cultural Idiom
This phrase is a cultural idiom, understanding it can make English TV shows or books clearer. 
In the novel, the hero's true colours were revealed as deceitful.