Godan verb with 'mu' ending, Intransitive verb
to be strongly attracted (by); to be utterly charmed (by); to be completely captivated (by); to admire greatly; to fall deeply in love (with); to fall head over heels (for)
彼女は一目で彼に惚れ込んだ。She fell in love with him at first sight.
Also written ほれ込む【ほれこむ】