I am trying to find the right definition of "hard" in this piece of writing:
newspaper
Looking for a tranquil hideaway after years as a paparazzi magnet, Mr. Frazier bought the single-level home on a one-acre property for $215,000 in 1979, while visiting St. Croix with his 12-year-old son, Walter III. He was shopping for a condominium, but instead fell hard for a house on hilly terrain with four tentacle-like columns that reminded him of a space ship.
There are many definitions for "hard" What does "hard" in "fell hard for" mean in this particular situation?

