CHOU!!! TENSAI HATSUMEI REIJOU NO POWERFUL RYOUCHI KAIKAKU

Description

The second daughter of Count Landourier, Marianne, is a genius girl who loves books. Her current problem is that she is shunned by her elegant older sister because she lacks the gracefulness of her daughter... However, Marianne, who is always positive, gradually melts her older sister's stubborn heart with her natural cheerfulness.
Furthermore, her innocence seems to have attracted her interest as well as her second prince -!?