In the New Testament, "paradise" is simply another word for heaven, the dwelling place of God. Just as Jesus is now in heaven, so we too will be with Him in heaven someday if we have trusted Him for our salvation.
In English, we often use the word "paradise" to describe any place of beauty and happiness and security; we even have "paradise" motels and "paradise" cafes! But only heaven perfectly matches this description of paradise, for it alone is a place of perfect and lasting beauty and happiness and security. Only in heaven, the Bible says, will there be "no more death or mourning or crying or pain, for the old order of things has passed away" (Revelation 21:4).
Why did Jesus promise this criminal, "Today you will be with me in paradise" (Luke 23:43)? The reason is because this man (unlike his fellow robber) knew he needed to have his sins forgiven, and he believed only Christ could forgive and save him: "Jesus, remember me when you come into your kingdom" (Luke 23:42). He could not depend on his good works–for he had none. He could only depend on Christ–and that was all he needed.
The same is true with us. Only one thing will keep us out of heaven, and that is our sin. But Jesus Christ came to take away our sins by His death on the cross. Are you trusting Him alone for your salvation? If not, open your heart to Him today.