Repent and believe is basically wht the Bible teaches. Clearly you are aware of your sinfulness so I am presuming you have repented, in other words, decided to turn from your old ways to God's. And it would appear you are aware that you cannot do anything to save yourself. That is clear from your message.
So all that is left is to believe in Jesus Christ. Believe that He is who He says He is and did what He said He did— namely that by His sacrificial death on the Cross He paid the full price for your sin and opened the way to Heaven. And believing means to not just say, "Oh, yeah, He died for me" like you would say there's a bunch of ice cubes in the freezer, but say it in utter thankfulness that because of Him you are going to spend eternity in Heaven. And then, if you truly meant it, you can know you are born again because the bible says you are ... and the evidence will be the desire in you to please God. It does not mean that you WILL please God. Certainly not in the beginning. But as the Holy Spirit works in you He will more and more bring you to the point where you recognize things that are displeasing to God and will be willing to say to God, "Such and such is not right in my life. I cannot remove it, but I want it gone because I want to please You! So, Lord, please remove it." Then trust Him to do so. It may take a while, or even quite a long time: but maintain your faith that you have the victory due to what Jesus did at Calvary and you will one day find the victory over that thing is now real in your life.
Growing in Christ—which is what we call sanctification—is a process. And it continues for all of our life. But our salvation itself is secure. The Holy Spirit inspired the Beloved Apostle John to write, "hese things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life."
We are also told in the Bible that the believer "who overcomes" ...
... will be given the right to eat from the tree of life, which is in the paradise of God (Revelation 2:7)
... will not be hurt by the second death (Revelation 2:11)
... will receive the hidden manna of God (Revelation 2:17)
... will receive authority over the nations (Revelation 2:26)
... will be dressed in white, symbolizing eternal holiness and purity (Revelation 3:5)
... will inherit the new Heaven and new Earth (Revelation 21:7)
... will be made apillar in the eternal temple of God (Revelation 3:12)
And who is the one who overcomes the world? The one who puts his or her faith exclusively in Jesus. (1 John 5:5)
You see we overcome because He overcame and now ministers for us in Heaven. So don't you worry about your salvation because you know you are not perfect. Don't listen to Satan's accusations; and don't go by your feelings. Instead, go by the Word of God and believe that because of Jesus, you are saved. Your desire to please him is the evidence.