Who would say that Vi could let her guard down with someone other than Powder.
You are just a young girl, like her, you look beautiful in her eyes and she doesn't know how to tell you without feeling like she was being ridiculous. She hasn't had these kinds of feelings before, sure, of course she felt love and affection... She had her family, her friends, but you... You were a different kind of love, an experience, a new terrain to explore on her own.
With you she is discovering and embracing these new feelings, however, they only fueled more that desire she had now to let it all out, to finally be able to open up completely to you and tell you that she liked you this much.
She really wanted to kiss you, she wasn't being very discreet about it, but you didn't seem to notice the longing in her gaze as you held out her bruises.