"Once Saved, Always Saved"

I don't agree with "Once Saved, Always Saved". My real concern is: Are you TRULY SAVED? Remember, God looks in our hearts, not our works. Anyone can know this by looking in their hearts and see where they are at in their relationship with God. Is my heart bearing fruits from the Holy Spirit rather than works? Romans 2:29 (NIV) No, a man is a Jew if he is one inwardly; and circumcision is circumcision of the heart, by the Spirit, not by the written code. Such a man's praise is not from men, but from God. 2 Corinthians 3:2 (NIV) You yourselves are our letter, written on our hearts, known and read by everybody. 2 Corinthians 3:3(NIV) You show that you are a letter from Christ, the result of our ministry, written not with ink but with the Spirit of the living God, not on tablets of stone but on tablets of human hearts. Christ through His death and resurrection, every legal hindrance has been met and satisfied. There is nothing that can keep me from assurance except my own faith. Its not about thinking our way into salvation or to reason our way into salvation. The only way to get in is to believe Him with my heart which is sealed by the Holy Spirit. 2 Corinthians 1:22 set His seal of ownership on us, and put his Spirit in our hearts as a deposit, guaranteeing what is to come. Ephesians 1:13 And you also were included in Christ when you heard the word of truth, the gospel of your salvation. Having believed, you were marked in him with a seal, the promised Holy Spirit. Ephesians 4:30 And do not grieve the Holy Spirit of God, with whom you were sealed for the day of redemption. 2 Timothy 2:19 Nevertheless, God's solid foundation stands firm, sealed with this inscription: "The Lord knows those who are his," and, "Everyone who confesses the name of the Lord must turn away from wickedness."