Believe In Your Heart!
Romans 10:9-11 - 9 that if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved. 10 For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation. 11 For the Scripture says, “Whoever believes on Him will not be put to shame.”
In verse 9 we read that if we "that if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved." Gods plan for our salvation is in two parts, the first part was that Jesus died on the cross, he was buried, and God raised him up 3 days latter. This first part was on the grace of God in his plan. The second part of the plan is put on use humans, we have to believe that Jesus did died, that he was buried, and that he was raised from the dead 3 days later, and that he is alive today living next to his father in heaven. That believe has to be on our spiritual heart, if its not then we could not attempt at becoming saved. Then and only then, when we have it on our heart, then we can finish our part by sharing the good news with other people.