Furaku no Bishoujo Doukyuusei to no Love Comedy ga Easy Mode Sugiru Ken

After returning to my hometown for the first time in four and a half years, I learned a shocking truth at the high school I transferred to. For some reason, I'm supposedly in a long-distance relationship with my childhood friend and now classmate, Nanami Kousaka, who has grown into a beautiful girl. I have absolutely no memory of this, so what in the world is going on, Nanami?!

...Eh?

You got tired of being confessed to every day, so to keep the guys away, you made up a story about being in a long-distance relationship with me? And you're begging me to pretend to be your boyfriend? I guess I have no choice, I'll play the part of your boyfriend, but only while we're at school─wait... Do our parents believe in this long-distance relationship too?! There's no turning back now...

All romantic rivals have already surrendered and both our families are giving us their ultimate blessing! A very easy fake rom-com kicks off with the outer moat completely filled in!!

(Source: Kodansha, translated)