How can I know for sure that I am saved?

Assurance of salvation is meant to be a settled confidence, not constant anxiety, and Scripture gives us solid grounds for it.

1. God's promise: "whoever believes in him shall not perish but have eternal life" (John 3:16) and "if you confess with your mouth that Jesus is Lord... you will be saved" (Romans 10:9) — salvation rests on God's promise, not our feelings. 2. The Spirit's witness: "The Spirit himself testifies with our spirit that we are God's children" (Romans 8:16). 3. Changed desires: 1 John was written specifically "so that you may know that you have eternal life" (1 John 5:13), and points to growing love for God and others, and increasing hatred of sin, as evidence of genuine faith — not as something that earns salvation, but as its natural fruit.

If you have genuinely trusted Christ, your assurance rests on His finished work, not on the strength of your feelings on a given day.