We need to die to be born again, to be sterile to bear fruit.
We can be a seed or a grain with potential but if we have not died we will not see the fruit and we cannot see that for which we were called.
That change of nature comes with a genuine birth. Have you had a difficult situation that led you to think about a spiritual change?
When we are faced with danger, death or situations where we are not in control, we can understand that the only source of help is the Lord and that is where a change of nature comes.