affection.

infatuation
/ɪnˌfatʃʊˈeɪʃ(ə)n,ɪnˌfatjʊˈeɪʃ(ə)n/

noun

an intense but short-lived passion or admiration for someone or something.

Similar:
passion for, adoration of, desire for.

commonly known as..love at first sight.