แน่ใจว่า

Explanation

This expression consists of แน่ใจ, “to be sure,” followed by ว่า, which introduces the statement being evaluated. Its basic pattern is “subject + แน่ใจว่า + clause,” and it is common in both conversation and writing. The negative form ไม่แน่ใจว่า is especially frequent. When followed by a question word or an uncertain alternative, it can mean “not be sure whether…” or “not know exactly how/where/what….” This is a negative construction of the same core sense, not a separate lexical meaning. With ต้อง or ให้, the expression can mean “make sure that…,” especially in instructions, reminders, and safety-related directions.

Usage

Used when stating certainty about a fact or plan, asking whether someone is truly sure, or avoiding a firm claim because of uncertainty. It also appears in workplace reminders, procedures, and instructions requiring someone to make certain that a condition has been met.

Caution

แน่ใจว่า is normally followed by a clause. It does not cover every sense of “check” or “verify”: use ตรวจสอบ or เช็ก when referring to the concrete act of inspecting information, comparing records, or checking equipment.

1 be sure that synonyms

• คิดว่า

  khít wâa think that

  คิดว่า presents something as an opinion or belief and is similar to “think that.” แน่ใจว่า indicates a higher degree of certainty.

• มั่นใจว่า

  มั่นใจว่า also means “be confident that” and is especially natural for strong confidence in one's abilities or predictions. แน่ใจว่า more generally expresses certainty that a fact or judgment is correct.

• รู้ว่า

  รู้ว่า means “know that” and presents something as known information. แน่ใจว่า focuses on the speaker's confidence that the statement is correct.