One can have a genuine relationship with Jesus through being born again and regenerated by the Spirit. However like you wrote, you continue to work out your salvation every day as it is a process, not strictly a one-time decision made in the past. Some days are better than other days but these verses are examples of how we know we can have assurance:
1 Jn 3:10 This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not a child of God; nor is anyone who does not love his brother.
1 Jn 3:14 We know that we have passed from death to life, because we love our brothers. Anyone who does not love remains in death.
1 Jn 3:18 Dear Children, let us not love with words or tongue, but with actions and in truth. This then is how we know that we belong to the truth, and how we set our hearts at rest in his presence whenever our hearts condemn us. We know because the Spirit lives in us:
1 Jn 3:21 Beloved, if our heart does not condemn us, we have confidence before God;
1 Jn 3:24 Those who obey His commands live in Him, and He in them. And this is how we know that He lives in us: We know it by the Spirit He gave us.
1 Jn 4:7 Dear friends, let us love one another, for love comes from God. Everyone who loves has been born of God and knows God.