Kate has sinabi I pag-ibig you, but to Kevin the guy she married.
She hasn't sinabi I pag-ibig you on screen to Jack or Sawyer. In the episode "Every Man For Himself" she sinabi "Yes I pag-ibig him!" when asked sa pamamagitan ng that 'other dude' while Sawyer was being beaten to a pulp - though later in the episode Kate then takes back what she said.
Kate has not sinabi I pag-ibig you to Jack on screen, but it's pretty easy to assume from their time together off island with their engagement that she must have sinabi it to him at some point, we just haven't seen it. It's also fairly easy to assume that she is still very much in pag-ibig with him, looking on her actions in season 5.
HI LISTEN AT THE END Nawawala THE 6TH SEASON SHE sinabi TO JACK AT THE LAST EPISODE KATE HAD TO GO TO THE PLANE & LEAVE JACK SO SHE SAID:"TELL ME I'M GOING TO SEE YOU AGAIN AND THEN SHE KISSED JACK AND SHE sinabi I pag-ibig YOU & JACK TOO.IT WAS THE LAST EPISODE JACK DIED IN THAT EPISODE ON THE ISLAND BUT THEY ALL LANDED IN LOS ANGELES CAUSE JULIET COULD BLOW THE BOMB & everybody landed in the los-angels at first they couldn't rem ember each other but then they could & jack & kate were together (jack + kate) so this is truth because it was 1 buwan or 2 months nakaraan the finally
HII!! No, Kate has never sinabi "I pag-ibig you" to Jack (unfortunately), but he already sinabi it to her in the end of season 3!! Kate has, however, sinabi "I pag-ibig you" to Sawyer in the last episode of season 4, when Sawyer was about to jump the helicopter. :/ As a jater I think she was carried sa pamamagitan ng the moment, she probably thought she would never see him again, or that he could die...