Lyric discussion by marxthebills 

Cover art for Wild lyrics by Beach House

I think "Hardest to say" makes more sense.

At 2:13, she clearly says HEARTLESS. You can definitely hear the T sound in there.

"Heartless" makes perfect sense in the context; the song seems to be about trying to honestly evaluate a relationship that isn't going anywhere.

the lyric book that comes with the vinyl says "heartless"