Heart Thief

me: I'm going to steal your heart.

her: omg that's so romantic!!

me, an organ trafficker: ( ͡° ͜ʖ ͡°)

Explanation

The humor comes from the unexpected and dark twist. The first person says they're going to steal the other person's heart, which is usually interpreted as a romantic gesture. However, the reveal that the first person is an organ trafficker gives the statement a literal and sinister meaning, creating a jarring comedic effect.