Certainly, definitely

Words that a speaker uses to indicate that he thinks something is certainly true or is certain to happen.

• What words indicate that something is certainly true?
  certainly absolutely definitely there is no doubt undoubtedly without a doubt without doubt without a shadow of a doubt unquestionably be beyond dispute there's no denying there are no two ways about it there is no question
• What words indicate that something will certainly happen?
  certainly definitely be bound to be sure to be certain to be assured of be only a matter of time be just a matter of time cut and dried you can bet your life you can bet your bottom dollar be a certainty be a foregone conclusion for sure
• What words indicate that something will certainly succeed?
  can't go wrong be a dead cert it's in the bag it's a safe bet it's a sure bet foolproof
• What words refer to doing something in order to be certain that something will happen?
  make sure make certain insure ensure see that see to it
• What words indicate that something is certain to happen and nothing can be done to stop it?
  inevitable whether you like it or not willy nilly be fated to be destined to predestined be meant to be pre-ordained doomed the inevitable
• What words describe something that is certain?
  certain definite conclusive
• What words indicate that something is certainly not true?
  absolute assurance assured can certain certainly certitude clear decided decisive definite doubtless established fixed guaranteed incalculable incontestable incontrovertible indisputable indubitable ineluctable inevitable infallible inescapable inevitable irrefragable irrefutable positive really set settled single-minded sure sureness trustworthy unarguable unavoidable undeniable unequivocal unmistakable unquestionable