* Origin: The word "opening" comes from the Old English word "openung," which itself comes from the verb "open." This root word doesn't have a double "n."
* Suffix: The "-ing" suffix is added to verbs to create present participles or gerunds. This suffix is added directly to the base form of the verb.
* Spelling rules: English spelling generally avoids double consonants in words like "opening." Double consonants are more common in words where the first consonant is followed by a vowel, as in "running" or "winning."
Therefore, the spelling "opening" with a single "n" is consistent with the word's origin and standard English spelling rules.