Responses
While I'd agree with you in most cases, in this case it makes sense that she hesitated.
She has no clue who killed her family. And then the only clue she finds is connected to Rias.
If she just went to him imidiately and asked him THAT would be super dumb. Because worst case scenario would be he has indeed been just acting and really was connected to her family's death in some way. Then he knows she found out and would kill her.
Of course we, as reader, know that's not true. But lippe doesn't know. Love can make one blind to the darker side of a person. ╮(￣▽￣)╭
I hate misunderstandings like this. I just feel it's so unnecessary when she could just ask why he had de silver plate. These scenarios always feel like lazy writting to me...