certify /ˈsɜːtɪfaɪ/ verb [T]
TRUTH formal › to say in a formal or official way that something is true or correct: [+ (that)] I certify that the information I have given is true. She was certified dead on arrival at the hospital.
CERTIFICATE › to give someone a certificate to say that they have completed a course of study: a certified accountant
HEALTH › to say officially that someone has a mental illness