
But Ripley has never run away from home? She tried to end the Duke's engagement but none of that involved her disappearing from home. I really don't see how this can make the Duke think Ripley is avoiding him. Furthermore, before, Ripley had never told the Duke how she felt. But now, she has confessed. So the situation before is very different from now.

The duke asked Silvia to keep an eye on Ripley so she doesnt escape and go to work on her business project with Etoile instead of preparing for the wedding. Silvia even said to Ripley "you can leave if you dont care that i get my throat slit" because the duke has been pressuring both Ripley and Silvia.
Now Ripley has been kidnapped but nobody saw her/know that (it was night and it was a unknown maid who baited her). So it is possible that the duke is gonna think that Ripkey went to work and Silvia failed to keep her from going to work thus failing her mission to keep an eye on Ripley thus risking to get her "throat slit".
I am so lost on how Ripley getting kidnapped is her causing trouble for others? Is there something I am missing? Did she organize her own kidnapping or didn't she just follow a maid in her own household?