If you say that someone is casting pearls before swine, you mean that they are wasting their time by offering something that is helpful or valuable to someone who does not appreciate or understand it.

“bacati bisere pred svinje”

 

I’m afraid you’re casting pearls before swine with your good advice – he won’t listen.

I won’t waste advice on John any more, he never listen to it. I won’t cast pearls before swine.

Some would not rightly appreciate the value of your frankness, and never cast pearls before swine.