Can anybody help me with the meaning of this expression, besides this other meaning
(The value printed or written on the face, as of a bill or bond )

In addition to the monetary/financial meaning, 'face value' refers to the (merely) surface value or importance of other things.

'Don't take his harsh comments at face value; he really has your interests at heart'
'Taking such peace initiative as a face value does not make one naïve.'
I understand, but how can I tell you? I am Vietnamese, and you?
I can't explain if you are not Vietnamese. Sorry.
 Mister Micawber's reply was promoted to an answer.