1. "I swear on Emma Swan."

2. "Killian, come back to me!"

3. "I believe what I'm trying to say is, your highness, you appear to be a natural. "

4. "I'd go to the end of the world for her. Or time."

5. "One of these days I'm gonna stop chasing this woman."

6. "Hook: What the hell are you doing? You're depriving me of a dashing rescue.
Emma: Sorry. The only one who saves me is me."

7. "I came back to save you."

8. "There’s only one rule, pick a partner who knows what he’s doing."

9. Hook: "There's not a day that will go by that I won't think of you."
Emma: "Good."

10. "Emma Swan: You are glad to hear I got my heart broken?"
"Hook: If it can be broken, it means it still works.'"

11. "I knew there was a little pirate in you!"

12. "My walls were up, but you brought them down. You brought me home."

13. Emma: "You traded your ship for me?"
Hook: "Aye."

14. "I can't lose you too."

15. Emma: "I'm going to choose to see the best in you."
Hook: "And I in you."

16. "Don't you know Emma? It's you."

I really like number 9.
What about:
"I hope it's my job to protect your heart"
"I know how you kiss I'd have gone after her."
"Emma, no! Please, don't do this." "I Love You."
"I just watched the man I love die. The worst part is I never told him I loved him. Not once."