Which phrase reflects a desire to have paid better attention during the lesson?

The phrase "I had paid more attention" conveys a sense of regret about not being more engaged during the lesson. It suggests that the speaker recognizes the importance of attention in learning and now feels a desire to have approached the lesson differently. This phrase reflects a reflective thought on past behavior, indicating that the speaker acknowledges a missed opportunity to learn effectively due to a lack of attention.

In contrast, the other phrases do not express a desire to have paid better attention. "I wish I had forgotten" implies a desire to erase a memory rather than to improve one’s learning experience. "I now wish I would ignore" suggests a wish to overlook information, which contradicts the idea of wanting to pay better attention. "I will pay more attention" looks forward with intent to change behavior, but does not express regret about past actions in the same way that "I had paid more attention" does. Thus, the selected phrase is the most fitting for expressing a desire to have been more attentive during the lesson.