There are many different ways to express a deep and romantic attraction to someone, and "in love with" is just one of them. Some common synonyms for this phrase include "smitten with," "enamored of," "captivated by," and "head over heels for." Other, more poetic options might include "charmed by," "beguiled by," "enchanted with," or "enthralled by." Whatever phrase or expression you choose to use, the sentiment is the same: you are deeply and passionately attracted to someone and feel an overwhelming connection with them that is hard to put into words.