Sentence examples for it is certain is from inspiring English sources

The air, it is certain, is often charged with noxious exhalations arising from the putrefaction of animal and vegetable matter... these exhalations exert a most important agency in the production of epidemic diseases".

On holidays not universally observed, like Veterans Day, my company will deliver only to businesses it is certain are open.

Whether it's SF or not is arguable (I think it is); what is certain is it's brilliant.

Others are unsure, but what is certain is it has been a tumultuous ride.

What is certain is that it is hardly ever swift.

One thing that is certain is that it will be a baseline battle.

The only thing that is certain is that it will be through a two-way conversation.

What is certain is that it's having a significant impact on the carbon cycle".

Check to be certain: is it really beyond hope?

It is certain to be spectacular.

It is certain to be a noisy encounter.