Hi, I'm trying to find a manga I read some time ago.
In the manga, a boy falls in love with a girl in his class, he later finds a mysterious shop that sells him a ring, the man in the shop says that if he manages to make the girl wear the ring she'll fall in love with him, but if he is rejected she'll hate him.
In the end, he spends years building a relationship with the girl, and when he proposes at last, he thinks "Wasn't the ring pointless" or something like that

Sorry, I forgot a lot of the details, so please tell me if you know of anything similar.
It might have been a one-shot, but I can't really remember

Thank you for your time