When the Knight of Cups shows up for feelings, I read it as "True Love." For me, this card usually points to a stretch of affection and attention - either your beloved will be really loving and attentive, or you'll be the one pouring it out, and yes, it can be totally swoon-worthy.
I don't agree with Zena on this. I think the knight, like the other knights, acts from his emotions, but he's not the fast, impulsive kind you get with the Knight of Swords or Wands. He moves more gently, follows his heart, and expresses that love to his Beloved.
It also brings that muse-driven energy, the urge to create haunting music or poetry, or to walk away from a boring job and chase a dream.
If you're asking about someone else's feelings, don't freak if they don't call right away. They're probably thinking of you, and when they do reach out, be ready to be swept off your feet. Just a playful heads-up: maybe open a decent savings account, because getting lost in the Knight of Cups' dreamy world can be rough on the wallet.
No one is purely the Knight of Cups, but everyone in love carries a little of his romantic streak. 🌹💖