I don't understand that expression "false". Is there somedy who can help me?
False is most often an adjective that means, according to the context "untrue" (a false report), "deceptive" (a false testimony), an incorrect piece (a false note in music), non genuine (false teeth), etc.
Here linked with friend, it means something that sort of is inclined to lead to a mistake.
A false friend (un faux ami) is an idiomatic expression to call a word of expression which looks the same in two different languages but with a different meaning. Ex/ 'a prejudice' in English is most often 'un préjugé' while 'le préjudice' in French is a harm, a damage in English.
Correction : ... a word OR expression...
in the mood of love : a false lover is unfaithful, is not he ?
..is he not?
But what's the complaint? As long as the illusion is perfect? Who cares?