Has God, "Opened the heart", of these we are asking about? that "believe","have faith","decide",etc.

That scripture indicates that a Sovereign act of God is necessary for our reception of the Truth. Reminds me of Jn 6:44 in principle.

 

Jesus opened up some hearts so that they could understand the scriptures Lk 24:44-45

44 And he said unto them, These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me.

45 Then opened he their understanding, that they might understand the scriptures,

Its the word opened Paul uses in Acts 16:14 Its the greek word dianoigo:

1. to open the mind of one, i.e. to cause to understand a thing
   
   
   1. to open one's soul, i.e. to rouse in one the faculty of understanding or the desire of learning