Twilight was already falling and, owing to the rugged nature of the ground, he was by no means sure of his position.
I seem to have been hearing noises in the wood, for a long time; and when I heard you coming, I was by no means sure that it was not an illusion, like the others.
We also took with us provisions, clothing, and a tent, for I was by no means surethat we should find either food or shelter on the oasis.
One cannot shed oceans of tears and leave no sign; and Janet, by no means sure of herself, sat with her face turned from the light, intently gazing on the very small print of the Bible in her hand.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "means sure" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.