I really quite enjoyed this manga. It's super cosy, an isekai that reminds me a lot of The Savior's Book Cafe Story in Another World. I also really like the art style. 

The central premise is that Sei is summoned to the world along with another woman, and then completely ignored by the prince in favour of the other person. As yet this is unexplained and doesn't make a lot of sense, but Sei is such a likeable character and her actions so relatable that I very quickly overlooked my confusion. 

I'm aware there's an anime adaptation and honestly it might be the next anime I try.