How to tell her I'm not interested?

So I went on a few dates with this girl a few years ago, and back then I was not really that interested in her (she's not really my type), so when we stopped seeing each other I was kind of relieved. However she recently texted me out of the blue saying she wants to go on another date, and for some reason in the moment I said yes. I'm not really interested in her and I'm also not that keen on watching a movie with her either... I'd feel bad saying that to her though...

What do I do now? I need help 😕
How to tell her I'm not interested?
Post Opinion