confirmation - noun

additional proof that something that was believed (some fact or hypothesis or theory) is correct

information that confirms or verifies

making something valid by formally ratifying or confirming it

a ceremony held in the synagogue (usually at Pentecost) to admit as adult members of the Jewish community young men and women who have successfully completed a course of study in Judaism

a sacrament admitting a baptized person to full participation in the church

confirmation - thesaurus

check   ratification   substantiation   verification