Despite the twists and turns, with Ailish recognizing him, Rest's official entry into the Rosemary Marquis family as a son-in-law was decided.
Even his father and head of the household, Albert, reluctantly acknowledged that Rest would marry the two sisters, making their relationship officially recognized throughout the house.
If there's a problem, it's that Rest himself doesn't realize he's become the fiancé of the sisters.
He genuinely thinks he was welcomed into the mansion as an apprentice servant, as thanks for saving their lives.
He does feel a bit strange about how the sisters are getting closer to him, but he doesn't think of it as love.
It's less about being dense and more about lacking experience in being loved.
In his previous life, he was never loved by his parents and was too busy studying and working part-time to survive. While he had friends, he never had a girlfriend.