Fred/Helena and whoever else is good people!
Helena looked between the two of them, even more uncertain. She had no brothers or sisters, therefore, she wasn't aware of how complex their relationships could be. Threatening bodily harm though, she hadn't heard any of her friends speak that way with their siblings in her time. It might have been kept private and away from the public, much as it should have been done here.
"Ginny, then. It is nice to meet you. However terrifying you may be to me." Actually, Helena had a feeling that would have been a compliment, it was the reason she didn't hold back and think before saying it aloud.