Yes, God -- not Satan -- certainly is going to be the victor! At the end of time, the final battle in this great spiritual conflict will be fought, and God will triumph over Satan forever (see Revelation 20:10).
Not only that, but all the evils that have come into the world because of Satan's rebellion against God will be destroyed. Sin... sickness... death... sorrow... suffering -- all these will come to an end, and God's people will dwell safely in His presence forever. One of the Bible's greatest promises speaks of that day: "He will wipe away every tear from their eyes. There will be no more death or mourning or crying or pain, for the old order of things has passed away" (Revelation 21:4).
Why doesn't Satan just give up? The Bible doesn't tell us -- but one reason may be because he doesn't believe what God says about his eventual fate. The very first question in the Bible came from Satan's lips, telling Eve that God was a liar and His word couldn't be trusted (see Genesis 3:1-4). Satan's goal is to take God's place, and perhaps he still believes he can do it. But he can't.
Are you on the winning side? Is your faith and hope in Jesus Christ? Don't be deceived by Satan's temptations. He promises happiness and peace if we'll only follow him -- but his promises are a lie. Instead make it your goal to follow Christ and His Word, for He alone brings us victory.