It is not an old expression, and definitely is not a toast. Suppose you get very late one day to the office, for whatever reason, and say to your boss (assuming you are not the boss): " I am/was late, as the road was blocked for a long time due to the search of meteorite fragments by the National Institute of Petrology " , please excuse me. This little story (true or false, I won't say) will happily be tagged under the category: se-non-e'-vero-e'-ben-trovato 'Ben trovato' here with the meaning: cleverly built, or cleverly found out. How to categorize this expression in a syntax context ? I would say: --- 'extended-adjective' (aggettivo esteso) -- metaphorical adjective (metafora aggettivante) alternatives: se non e' vero e' ben pensato se non e' vero e' ben costruito If not clear, please tell me, I'll gladly make up another little story. Be warned: Italian politicians are very very clever in this (se-non-e'-vero-e'-ben-trovato) job.

in my country was used sometimes some time ago....it means that your explanation about something is not convincing but that you gave an explanation that doesnt sound like an evident lie!. (of course, using italian as here nobody has italian as mother tongue!-----a kind of "opera bufa"- like expression)...

It is the mark of good fiction.

It is commonly used in literary and philosophical circles, if a bit incorrectly, to mean "even if it's not true in a literal sense, in a deeper sense, it is true."

i'm italian and i never listen this toast