I think it would be Tsugami because she began to like him later on after meeting him, she thinks he is with Chitoge and is thinking more of his happiness than hers. New reason she trusts Raku with the one that is most important person to her: Chitoge.
Onodera because she liked him since middle school and has also been helping him keep the fake lover thing a secret even though that means it would be difficult to get close to him as a lover.
Maybe Onodera's little sis to because she began to like him after meeting him to but is also supportive of her sister. The others like him as the past person not the current.
The keys and locket part is a little off, I mean you can't love a person based on a past event 10 years ago as a 5-6 year old I mean every thing is so confusing at that age that you forget every thing and you just start to develop a personality.
P.S. Him as a child is different as a teen/adult.
Edited by animerajen, 04 March 2015 - 05:38 AM.