Help find!

It was either isekai or historical setting, the characters are still kids. The girl tries to avoid the Prince or something but he comes to her house the next day and announces their engagement to her anguish. He's pretty possessive over her cause when she meets a glasses boy (prime ministers son or some kid of scholars son) and starts to study and read together with her a lot of times in the library, he's mad and they both have a confrontation like 'why are u spending so much time with my fiance'. There were only a few chapters if I remember correctly