Because he and his friends survived, now he can help her mother.
Doing so means traveling to Beastkin territory, which is quite far away.
Ken wants to help if he can; he just needs to ask Rose and the King.
Ken gives her a diary like the one he used to help him process the hardship he went through.
Its here where I declare that I love Felm with all my heart and cant get enough of her!
Shell be in good, if rough, hands.
Rose assures Felm that Ken will be just fine, and wont be easily hurt by anyone.
Rose makes Ken more happy than he expected by telling him she expects great things from him.
