It is not our character that keeps us spiritually safe, but it is our God. When we believe in Jesus Christ, we shift the responsibility of saving us and keeping us safe from ourselves to God. That is the basis of Christian confidence. Paul proclaimed this at the end of 1 Thessalonians.
Now may the God of peace Himself sanctify you entirely; and may your spirit and soul and body be preserved complete, without blame at the coming of our Lord Jesus Christ. Faithful is He who calls you, and He also will bring it to pass (1 Thessalonians 5:23-24).
Our future depends upon the loyalty, faithfulness, and the consistency of our God. God's faithfulness is always the basis of our secure future in heaven, and not our own character. The principle in this is that the more we trust in the faithfulness of our God, the more faithful we will be. We can look forward to the coming of our Lord Jesus Christ with a sense of confidence. The more we look forward to that event the more our hearts will instinctively prepare us for his coming. Paul told us that every aspect of who we are, spirit and soul and body, will be preserved complete and without blame at the coming of our Lord Jesus Christ. Our future belongs to God and not us.