Imagine finally confessing to your crush because you needed to let it out after keeping it for so long and you finally want to be honest. Not expecting anything much other than a rejection because he is already taken. So you want to move on.
Then suddenly you find out he used to like you too.
Anyways, it was her own fault for distancing herself and not being on his side. Her own heartbreak is what came around after her own betrayal. So I guess it implied he did like her and she got that, so that is why she lost her composure.