'Sure' in the Bible

Then Zechariah asked the angel, "How can I be sure of this, since I am an old man, and my wife is getting older?"

Even the very dust of your city, which cleaveth on us, we do wipe off against you: notwithstanding be ye sure of this, that the kingdom of God is come nigh unto you.

But be sure of this: if the homeowner had known at what time the thief were coming, he would have watched and would not have let his house be broken into.

Jesus said to his disciples, "Stumbling blocks are sure to come, but woe to the one through whom they come!

So also, when you see these things happening, you may be sure that the Kingdom of God is near.