THIS SENTENCE! PLEASE HELP!! I BEG AND SUPPLCIATE YOU ALL! WHAT DOES THIS SENTENCE MEAN? Could someone please?

My reading of this paragraph is that, immediately upon becoming engaged to Banio, it is Portia who provides the ring to seal the engagement, which would seem to indicate that she is in control, i.e. Portia 'owns' Banio rather than Banio 'owning' Portia.