Is there any non-Calvinist that can answer this simple question; any, just one? It is essential for salvation for without it, no one can be saved. And yet, it seems that it is beyond the Arminian gospel to explain.
If you confess with your mouth the Lord Jesus and believe in your heart that God has raised him from the dead, you shall be saved. For with the heart one believes unto righteousness and with the mouth that confession is made unto salvation.
Bottom line appears to be choice, doesn't it?
If that's not what you mean by "how" you're going to have to share the "particularistic" definition of what your local group of calvinists mean by the word "how."