credible
naive
naïf
overcredulous
unquestioning
accepting
apish
asinine
batty
befooled
beguiled
believing
besotted
brainless
buffoonish
childlike
cockeyed
confiding
crazy
daffy
daft
dazed
dependent
depending
dizzy
doting
dumb
dupable
easily taken in
easy of belief
fatuitous
fatuous
flaky
fond
fool
foolheaded
foolish
fuddled
futile
gaga
goofy
green
guileless
gulled
gullible
idiotic
imbecile
inane
inclined to believe
inept
inexperienced
infatuated
innocent
credulity
delude
devout
good-natured
ignorant
impressionable
ingenuous
inquisitive
misguided
sanguine
simple-minded
sincere
superstitious
thoughtless
timid
trustful
uneducated
unsophisticated
unsuspecting
incredulous