In my novel, my character is at first cowardly, kind polite and saintly. but now I want to give him a more robust nature - ruthless and brave , due to an accident that he met with. How do I bring it about? Announcing it blandly to the reader or in a hidden manner, letting the leader find out for himself ?
I agree with Susan. Just let it happen, otherwise it would sound contrived.
I think you'd have to show it by his reaction in different situations, which would also interest & draw in the reader. It would be too boring to just announce it, in my opinion anyway.