testify
tes.ti.fy \'tes-t*-.fi-\ vb [ME testifien, fr. L testificari, fr. testis witness] 1a: to make a statement based on personal knowledge or belief : bear wit ness 1b: to serve as evidence or proof 2: to express a personal conviction 3: to make a solemn declaration under oath for the purpose of establishing a fact (as in a court) 1a: to bear witness to : ATTEST 1b: to serve as evidence of : PROVE archaic 2a: to make known (a personal conviction) : PROFESS 2b: to give evidence of : SHOW 3: to declare under oath before a tribunal or officially constituted publi c body
Webster's English Dictionary