What can the object of a preposition function as in a sentence

For i assure you (what credit my assurance may have with you, i cannot tell, but what credit it shall deserve to have, the sequel shall declare) i will never in that matter conclude any thing that shall be prejudicial to the realm. for the weal, good and safety whereof, i will never shun to spend my life . . –response to parliament's request that she marry, queen elizabeth i what is queen elizabeth's purpose in this passage? to inform her audience about new safety measures she wishes to take to protect england to entertain her audience by providing details about the sequel to a famous play to persuade her audience that she will not make any personal choices that harm england to inform her audience that she has made the decision to get married