Otona no wo Benkyou, Hajimemasu.

In high school, Emi was rejected by her crush because of her bad grades. Her frustration over her heartbreak ignites her passion for studying for the first time in her life, and after a lot of hard work, she overcomes her "stupidity" and got a good government job. One day, she meets her lost love Kei again, but his appearance has changed 180 degrees from his student days. A reversal romance between a former idiot and a former genius, who "learn to love" and "learn to learn" from each other!

(Source: eBookJapan, translated)