vouch Synonyms

attest guarantee warrant declare confirm aver affirm assure asseverate verify uphold undertake testify swear support substantiate state secure cross heart vow state under oath Arabia apologise take the stand plea-bargain bear witness to obtest swear on bible witness warranting prove protest depose corroborate circumstantiate certify avow avouch authenticate adduce assert endorse ensure enure promise profess predicate plight pledge mortgaged