How to use "proving" in a sentence

Stryker and the woman were proving to be worthy opponents.

Mr Kyrle told us that if she could not remember what had happened to her, we had no hope of proving her identity.

This was the proof I needed! The death certificate said that Lady Glyde had died on 25 July, and here was a letter from Sir Percival proving that she was still alive on 26 July!