〜ないわけがない

there is no way it won't...; it is impossible for it not to...

1. Overview

"〜ないわけがない" is used to convey the speaker’s strong belief that something will certainly happen or that some result is inevitable. Although it is a negative structure, the meaning is positive, affirming that something is bound to occur.

2. Structure

• Verb (ない form) + わけがない
• い-Adjective (ない form) + わけがない
• な-Adjective (ない form) + わけがない
• Noun + がないわけがない

3. Usage Explanation

1. Expressing Certainty: This structure is used to assert that something will definitely happen or that some condition is inevitable.

   • Example: 努力すれば成功しないわけがない。
     (If you work hard, there’s no way you won’t succeed.)

2. Emphasizing Possibility: It emphasizes that a certain event is bound to occur, or that a particular outcome is guaranteed.

   • Example: こんな美味しい料理、みんなが好きにならないわけがない。
     (This delicious food is impossible for everyone not to like.)

4. Example Sentences

1. 彼が本気で勉強すれば、合格しないわけがない。
   (If he studies seriously, there’s no way he won’t pass.)

2. そんなに練習したんだから、失敗しないわけがない。
   (Since you practiced so hard, there’s no way you will fail.)

3. この映画が面白くないわけがない。
   (There’s no way this movie isn’t interesting.)

4. 彼の性格を考えると、手伝わないわけがない。
   (Considering his personality, there’s no way he wouldn’t help.)

5. Key Points to Note

1. Although it is a double negative structure, the meaning is positive, emphasizing strong certainty that something will happen.
2. "〜ないわけがない" is often used to express strong confidence or certainty about an event or outcome, and the tone can be quite assertive.

6. Similar Grammar

• 〜はずがない: This expression conveys that something is impossible, which is the opposite of "〜ないわけがない."
  • Example: 彼がそれを知っているはずがない。
    (There’s no way he knows about that.)

7. Alternative Grammar

• 〜に決まっている: This expression also conveys strong certainty or conviction, similar to "〜ないわけがない."
  • Example: 彼が優勝するに決まっている。
    (He is definitely going to win.)

8. Summary

"〜ないわけがない" is a double negative structure used to express strong certainty or inevitability. It emphasizes that something is bound to happen or that a particular condition will definitely be true. This expression is commonly used in both formal and informal speech to assert confidence in an outcome.