「確実」(かくじつ) means something is definite, reliable, or sure to happen. It conveys a strong sense of certainty and trustworthiness, often used when an outcome is guaranteed or a method is dependable. It can be used as a な-adjective or adverb. Example: 明日の会議には確実に出席します。 (I will definitely attend tomorrow's meeting.)

疑う余地がなく、確かで信頼できること。