In 'The Last', Sakura quoted "When a girl truly falls in love, her feelings change easily. Honestly, they can't change at all."

This quote means that from the start, Sakura had feelings for Sasuke (obviously) and it also means that Sakura feelings wouldn't change that easily for she can just automatically love Naruto out of the blew, or maybe at all. And Sakura proved that right there.

FYI, this is could literaly be a NaruHina fact, but mainly SasuSaku.

-AniArmi