Note: This answer is a frame challenge.
The checkbox should not be there at all.
According to your screenshot, your users use your search engine to find a solution to their billing problem.
You write that your users "weren't compelled enough to select [the checkbox]". And why should they be?
They have a billing problem, and so, their number one ...
Try using actions that represent a clear choice between two outcomes. Phrase in the form of a question or a command to address them directly.
Your question is about graphic emphasis, but I'm suggesting rethinking the checkbox and the writing you have.
A checkbox is associated with a setting or configuration. Here, you're asking the viewer to leave an ...
There really isn't a design pattern that would address this, since design patterns are more abstract concepts for solving problems that still require some implementation and testing to see if it is effective.
So while this is primarily a visual design issues, and therefore falls into the domain of Graphics Design StackExchange, the principles used in the ...