If I have true saving faith, can I be sure that I am saved?
Yes. When a person has true saving faith, God Himself has elected and brought that person into salvation, and no one can lay anything to the charge of God's elect. That salvation is all God's doing, so no one can touch it or take the believer out of His hand.
Les explains that these verses hammer home the idea that once God has put the finger on us, has elected us, and we have responded and entered into His tremendous salvation, nobody can touch that. It is all what God has done. He warns that anyone who says no one can know they will go to heaven is totally unaware of true saving faith. If your faith is sufficient to believe the Gospel and bring you into salvation, you should have enough faith to take God at His word that you are His. No one can take us out of His hand. Les also notes that he cannot see God electing someone who would later choose to reject Him.