I'd never leave you behind.

[Said without even a trace of hesitation. Because she wouldn't. She'd never leave any of her friends behind, but especially not Akane.]

Ahaha... I know the feeling. Your heart's just going thump-thump-thump non-stop and it feels your chest will just go boom! because it seems like it's beating too fast to be possible, right?

[Perhaps not put in the most eloquent way, but it gets her point across.]

I know, because that's how I feel too.