"I am sure Beth said "that you are right.""
Here's why:
* Quotation marks: The words "that you are right" are a direct quote from Beth, so they need to be enclosed in double quotation marks.
* Period: The entire sentence ends with a period, so the closing quotation mark for Beth's quote is placed before the period.
* No comma: There is no comma needed between "said" and the quote because the quote itself is a complete sentence.
Therefore, the sentence with proper punctuation is: "I am sure Beth said "that you are right."