AWWW~♡
True, Amane is nowhere near the levels of sheer awesome that Gon is, but... so CUTE, damnit. Particularly because it's the fact that Hajime is being his usual jerkass self what makes her go hug him happily... and then, obviously, the fact that Hajime, who is just about as standoffish as they come, grins and strokes her hair. XD
Of course, Gon would have immediately KNOWN the other one wasn't HER inappropriately older intended boyfriend. But not everyone can be as awesome as Gon is. The universe would probably implode.