Another word for make sure of

I will make sure of it.

This time she determined to make sure of her convert.

A new world was discovered, for the sake of which everything else was abandoned; to make sure of that world insight and intelligence were freely sacrificed; and, in the light that streamed from beyond, the absurdities of the present became wisdom, and its wisdom became foolishness.

The first step was to make sure of the city trainbands: of the garrison of Copenhagen the king had no doubt.

Finally, more in the spirit of orthodoxy, he used the same arts to make sure of heaven.