[request] Show fake facebook Sponzored ads on my local PC?

Hello,

is there a way to make a script in Greasemonkey, which would show fake sponsored ads on my news feed? I can do almost anything with static websites, but Facebook's code is way too complicated for me.

What for: I'll keep the details for myself, but I'm planning to propose my girlfriend and I've thought of an amazing way to do so, but to do that, I might need her to "find" an ad, click on it and read the content. And since she doesn't have any website she visits often, nor she reads her emails, Facebook is really the only choice.

Thank you very much for any help?