Sometimes other people know you better than yourself. Should be the same for your waifus.
Also, if you're not at least 25 or so Genny's not interested lmao!!
Yeah, they're different convos. Also, I'm not sure if the English version does this, but Azura has three different voiced confessions in Japanese. If you play the game in the order of Birthright -> Conquest -> Revelation, you actually get this weird thing where Azura's voiced confessions get more and more passionate the more routes you play. General gist is Birthright = I'll like you but I think I'll love you someday, Conquest = I love you, Revelation = I've loved you since forever