The sentence you provided is an example of using a direct address in English, which requires the use of a comma. In this specific sentence, the name "Rima" is considered a direct address. Let's break down the sentence to understand the placement of commas:
"I know that you want to learn to drive" - This is the main clause of the sentence.
"Rima" - This is the direct address. It identifies the person being spoken to directly in the sentence.
"but you are too young." - This is the continuation of the main clause.
In English grammar, when you address someone directly within a sentence, you should use commas to set off the name from the rest of the sentence. Thus, the correct punctuation for the sentence is: "I know that you want to learn to drive, Rima, but you are too young." The comma provides a natural pause in the sentence and makes it clear that Rima is being directly addressed.