How do you express hatred towards someone you hate very much?

To be up front with you, you should not hate no one! You should forgive them of what they did or didn't do (not forget but forgive) and let God Deal with them. If you can not forgive them then you are basically saying that you are above God, God hates no one he hates the sin that they do.

Another Excellent reason to strive not to hate is that hate is the poison that destroys the hater, not the hated.

It is never easy to overcome some of our basic emotions, but as you try, you become a stronger, more powerful person.

That's three reasons to make the effort!