Hime ja Nakereba Nagutteru

Hime ja Nakereba Nagutteru (姫じゃなければ殴ってる) is a manga series by Taichi Nagaoka. It was serialized in Comic Meteor.

Plot
Upon reaching fifteen years of age, the princess of the Kingdom of Akura, by custom, must undertake a baptismal journey. Nanami, a mage, is assigned to accompany the current princess, Princess Miki. Problem is, Miki is a trashy bitch that selfishly and arbitrarily demands that they kneel, which is a big pain. They'd blast her with their magic, but she's royalty, and furthermore, the inheritor of the sacred power which is of vital importance to the world—so Princess Miki is doubly untouchable.

Can Nanami safely finish this stressful journey and finally be released from the princess' company?!