Conversion of Paul -Acts 9

Acts 9
I've always wondered what caused Paul to have such a dramatic conversion, what kind of inheritance he's got that gave him such favour with God. Can God convert my unsaved friend or loved ones like that?
Reading this passage again I was reminded of a story Merilyn Hicky told. There's this lady who wants her daughter to go to Bible college and become a missionary. Then the daughter was raped and murdered. The Lord told the lady to forgive the murderer and to send him a Bible. It was very hard for her to do so but she obeyed. Then later the murderer got saved and brought lots of people to salvation in prison, and the lady actually funded him to go to the Bible college and he became a missionary in place of her daughter.

This story made me think that the cause of Paul's conversion is because of Stephen's martyr and his prayer:"Lord, do not hold this sin against them!". The Lord answered his prayer by raising one of his persecuters in place of him.