Can we know for certain that we are saved? The Bible says, "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." Romans 10: 9.
Confess and believe ... and you will have salvation.
"For with the heart man believeth unto righteousness, and with the mouth confession is made unto salvation." Romans 10:10
Notice what the verse does not say: live a perfect life, be good to everyone, never fail, always smile - and you will be saved. Nobody can. Impossible. Just confess and believe. Salvation will come. It's so easy ... and so hard.
God wants us to know that we are saved, because saved people are dangerous, willing to face the world, not afraid of the consequences since we know that, whatever happens, we will have eternal life. "There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit." Romans 8: 1
May the world take care!