"Take something at face value" is a commonly used idiom in the English language. To take something at face value is to simply accept it for what it seems to be on the surface. This idiom assumes that a piece of information has been given, and the recipient acknowledges it and believes it without putting any thought toward ulterior motives, hidden meanings, or anything else not blatantly apparent on the "face," or surface, of the information.
The origin of this idiom is reported by several dictionary and etymology resources, and is believed to have something to do with money. The face value of a piece of money is the exact amount printed on its front, or "face," with no second-guessing or questioning needed. Therefore, to take something at its face value is similar to accepting unquestioningly the worth of a piece of money, because the information is accepted with no further thought or consideration.
An example of correct usage of the idiom would be an individual saying to another person, "Please tell me outright what you are thinking. I cannot easily pick up on hints, so I just take everything you say at face value." This means that the individual does not feel able to search out hidden meanings and subtle undertones in the conversation, and instead wishes to be told information in plain terms that can be taken literally without the need to assume or decode anything. An incorrect use of the idiom might be, "I have taken what he said at face value, but I still think he might be misleading me." In this case, the individual has not really believed the speaker, because the assumption is still there that there are hidden meanings or misleading pieces of information.
Often, the tendency of people to take things at face value is taken advantage of by advertisers and other people or groups that stand to benefit from a slight deception. Advertisements frequently use "fine print" to modify an earlier, more eye-catching statement, providing a hidden truth that many people will fail to notice. For example, if a person accepts at face value an advertisement heard on the television that he or she can purchase a new car for an outrageously low price, that individual will likely be surprised to learn upon arriving at the car dealership that an outstanding credit score or other qualifying requirement must first be met.