Evidence that if a person is certain that he is in a state of purity, then he doubts whether he has committed hadith (broken his wudu’), then he prays with his purity like that
The Messenger of Allah (ﷺ) said: If any one of you has pain in his abdomen, but is doubtful whether or not anything has issued from him, be should not leave the mosque unless he hears a sound or perceives a smell.