Some people will never truly hear you when you speak no matter how hard you try.
In those circumstances the solution is never to try harder.
You might think that the harder you try they’ll eventually come around and hear you out. But the thing is some people aren’t interested in being wrong.
Some people aren’t interested in hearing a perspective that contradicts their own.
And even if they realise that they were wrong and the information you shared had changed their mind, they’re more likely to dismiss that.
When a person is more interested in being right than being open to new information, it might be a waste of time trying to get them to listen.