0 to say in a formal or official way that something is true or correct -- stwierdzać, potwierdzać
[ + (that) ] I certify that the information I have given is true.
1 to give someone a certificate to say that they have completed a course of study -- przyznawać dyplom
a certified accountant
2 to say officially that someone has a mental illness -- stwierdzać chorobę umysłową u