read some stuff where the premise was girl confesses to best friend and either because of pity and/or out of not wanting to lose her friend, she plays along and go out with her while trying to force herself to fall in love with girl A.

Is it this? Also, try using this dedicated thread next time.

That's not the one

Any other clues?

Is it maybe I Don't Know if This is Love?

Yup that's the one