To be honest, this is a rather weak manhwa. MC motivations, best boy's motivations, the prince's motivations, even the villain(s) motivations are all fairly surface level and don't amount to much in the course of the story.
But I think that's fine? This is just a very mellow and slow burning manhwa about a lady bringing her love of tea to the country and being cute with her husband, with a bit of drama sprinkled in just for a bit of change. And it's quite good at being just that, even if it lacks the excitement other manhwa have.