take at face value, to

take someone or something at face value

to accept someone or something just as it appears; to believe that the way things appear is the way they really are. He means what he says. You have to take him at face value. I take everything he says at face value.
See also: face, take, value

take something at face value

to accept something exactly the way it appears to be. I don't know whether I can take her story at face value, but I will assume that she is not lying. The committee took the report at face value and approved the suggested changes.
See also: face, take, value
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

take at face value, to

To accept something or someone at its apparent worth. The transfer of face value from monetary currency to other matters took place in the nineteenth century. “He must take advertisements of publishers at their face value and regard them as what they claim to be,” wrote J. L. Whitney (The Literary World, 1883).
See also: face, take
The Dictionary of Clichés by Christine Ammer
See also:
  • palm off, to
  • be taken at face value
  • at face value
  • devil in disguise
  • chalice
  • a poisoned chalice
  • a plague on both your houses
  • (someone or something) strikes again
  • catch more flies with honey than vinegar, one can
  • skip bail