When expressing an intense interest or attraction towards something, the phrase "is fascinated with" can be replaced with a myriad of synonyms to convey the same sentiment. Some potential options include "is captivated by," "is entranced with," "is enamored with," and "is spellbound by." Additionally, phrases such as "is absorbed by," "is obsessed with," and "is fixated on" can be used to suggest a stronger level of interest or preoccupation. Ultimately, the selection of the best synonym to use will depend on the specific context and degree of emotion being conveyed.