Final answer:
Pearl responds lovingly to a character named Stuart, which is evident from her affectionate reaction to his gift of a ring and her eagerness to return to live with him.
Step-by-step explanation:
The visitor to whom Pearl responds lovingly appears to be a character named Stuart, based on the provided quotes. In particular, there's a passage where the character speaking to Stuart responds with affection upon being assured she will be living with him, as she says, "Of course I am coming back," and expresses gratitude for a gift of a ring he gives her, "It is so like you to remember," implying a deeply felt love.