Kinkyori Renai, Tonari no Kaibutsu-kun Recommendations
The female lead is very studious and falls in love unexpectedly; they have a somewhat similar character. The male lead does things unexpectedly that surprises the female lead developing a cute & romantic relation ship. These two mangas have very similar genres and gives a very comedic feeling.
Both featuring a strong female lead excellent in her studies and slowly changes for her love. Although in this story both are students, but the female leads are similar, so if you like Umi you'd love Shizuku from Tonari no Kaibutsukun just as much!