It is not that we will never sin again once we have been saved, our human nature is still one of selfishness and sin. But if the Holy Spirit has truly become part of our heart, of ourselves, then his presence will change our thoughts and our desires. It should be that you no longer sin intentionally, no longer continue to only satisfy your selfish desires, and when you do sin there is conviction and remorse inside you for it. It’s not that we can’t go on sinning, it is that we won’t want to because our heart and mind will cry out against such things.