You can't make anyone do or realize anything.
It's a little like making someone like lobster who simply can't stand it. Sorry, I don't mean that anyone is getting sick thinking about you, but it's designed to get an image in your mind that you just aren't wanted anymore by one particular person. SOMEBODY out there will appreciate you!
We can't make you realize that it's time to let it go and move on either. You have to do that on your own too.

You don't, in fact it is your issue that you need to deal with, as to why you want to make them.

You either want them to suffer, or you want to try and make them come back.

There is nothing you can say or do to make them realize this. If you were truly good to them and had a good relationship with them, by simply walking away and never saying anything again they will soon enough realize on their own what they lost in you, when the next person can't compare to how good you were. Plus by saying anything to them just pushes them further away from you. Walk away work on yourself and be the best you can be for the next person who comes along.

I completely agree because I kept saying things cause I was hurt and I know it pushed her away but I at least wanted her to feel my pain but I just started ignoring and letting that person go so I don't even know if she will realize even if I was a wonderful man and great person to her and treated her like a queen regardless of how she acted towards me gave everything and she ends up with someone else. Will she realize what she lost?

I completely agree because i kept saying things cause i was hurt and i know it pushed her away but i atleast wanted her to feel my pain but i just started ignoring and letting that person go so i dont even know if she will realize even if i was a wonderful man and great person to her and treated her like a queen regardless of how she acted towards me gave everything and she ends up with someone else. will she realize what she lost??

I doubt it, maybe if the new guy is a boob, but not worth the time worrying over it.