Explanation:

- If you could wait: This phrase is a conditional clause and is grammatically correct. It introduces a condition that needs to be fulfilled.

- For just half an hour: This segment correctly specifies the duration relevant to the condition and is grammatically correct.

- ?? You will certain: This segment is grammatically incorrect. The adverb "certainly" should be used instead of the adjective "certain" to modify the verb "will."

- Be able to meet her: This is a grammatically correct complement to "you will certainly" and completes the action anticipated if the condition is met.

Answer: Option 1 - You will certain