to be fascinated (by); to be captivated by; to be enchanted by; to gaze admiringly at; to watch in fascination
その景色に見惚れていた。
I was gazing at the scenery in fascination.
彼女の踊りに見惚れて声も出なかった。
I was so captivated by her dancing that I could not speak.
思わず見惚れるほどの絵画だった。
It was a painting so beautiful that one could not help but stare.