swear
warrant
swear blind
demand
guarantee
swear down
ensure
lock into
buy
asseverate
prove
insist
attest
if I'm lying, I'm dying
maintain
overpromise
claim
adamancy
carry conviction
drive home
ram home
press home
trust
avow
vow
yield
affirm
convict
pinky promise
preach to the choir
suppose
committed
fake the funk
aver
declare
cross my heart and hope to die
take
win over
truthen
oath
verify
believe
acknowledge
swear on a stack of Bibles
admit
affirmative
engage
pass one's word
true statement
probative
affirmation
mispromise
pill
show
truth
flatter oneself
concede
jump in with both feet
establish
pledge
trueness
promising
a promise made is a promise kept
assertorically
plight
God's truth
committedly
assertively
should
depose
insistently
put one's money where one's mouth is
truthify
assertorily
promise
good as one's word
sell
push
assert
elocute
convincedly
swan
sell on
vum
keep
adamantean
assure