I disagree, I do think Jake liked Liberty as a person and a friend, he just never really fancied her that much, hence the movie night clip. That's fair enough, you can't help who you find attractive in that way and who you don't.
I not a Jake fan as I think he should have been honest with Lib weeks ago that he wasn't that isn't her. However, I also recognise that is a spectacularly inarticulate man, to the point that just can't put what's going through his head into words at all.
It's not just that he can't find quite the right words, he just can't find any words and so he gives and mumbles something that makes no sense like 'you're my girlfriend'. There are clearly things that phrases means to him that he can't explain. I find it quite sad to see actually.