How to Know that You are Truly a Christian?
Becoming a Christian is an act of your will. God fully respects our individual wills. He invites all to believe in Him, but forces no one. Becoming a Christian is all done by our individual choice to respond to His invitation.
The Requirement:
If you have confess with your mouth (tell others) that Jesus is Lord (God and the Supreme Being of the Universe) and believe in your heart that God raised Jesus from the dead, You will be saved! Romans 10:10
You must take a public stand! Jesus said: IF you confess me before men, I will confess you before my Father (God) if you deny me before men, I will deny you before my Father. (God)
IF you have truly done this you will know that there has been an internal change that you did not make yourself. God (The Holy Spirit) promises to come and live inside the believer and teach and guide him. This will manifest in love for others and a desire to do what is right. It will also result in the manifestation through a growth process over time into these personal characteristics:
Love
Joy
Peace
Patience
Goodness
Kindness
Gentleness
Faithfulness
Self Control
Becoming a Christian is a one time act that will seal your eternal destiny.
Acting like a Christian isn't automatic and takes time and repentance. Repentance is simply changing your thinking and as a result your actions.
This change is done by learning the Bible and doing it. It does take time. Your old thinking and habit patterns don't go away just because you become Christian. This is our individual responsibility.