I haven't read the story this quote is apparently from, but it's been a couple of hours and no one's answered your question so I'll do what I can. I can tell you what can be inferred from the quote itself, but be aware I might be missing connections with the rest of the story.
The kiss is sudden, and apparently unexpected, at least by the woman. She blushes terribly, her face is bright red. She is also frozen, figuratively speaking.
We can infer that the woman is surprised and shocked, certainly. We can also infer that a reason exists for her blushing and freezing. But inferring what that reason is might be speculative. She could be embarrassed. She could be insulted. She could be really pleased. Or she could be a combination of all of these.
I suspect that the context of the story might reveal to you why she blushes and freezes, but I can't tell you for sure.
I hope this helps.