adverb, noun which may take the genitive case particle 'no'
repeatedly; over and over again
Describes an action done many times, often with a sense of thoroughness or persistence. Can modify verbs directly or appear with の before nouns.
彼は重々同じ説明を繰り返した。
He repeated the same explanation over and over again.
重々のお願
After repeated requests, I finally got his consent.
adverb
Used with verbs of understanding, apologizing, or knowing to emphasize depth or completeness. Common in formal expressions like 重々承知しております.
その点は重々承知しております。
I am fully aware of that point.
ご迷惑をおかけしたことを重々お詫び申し上げます。
I deeply apologize for the inconvenience caused.
何度も simply means 'many times' and is more casual and common in everyday speech. 重々 carries a heavier, more formal or emphatic nuance of repetition or thoroughness.
十分に means 'sufficiently' or 'enough', focusing on adequacy. 重々 in its second sense emphasizes a deep, full understanding or feeling, often in formal contexts.
Reduplication of 重 (じゅう, 'heavy' or 'layer'), emphasizing repetition or depth. The iteration mark 々 is used to repeat the kanji.