This is what my response to the lecture Queen Tatiana gave Rose in book 3 would have been, had I been Rose. Basically, it's a really long, eloquent, elaborate, polite, LONG way of saying "You're being stupid, get a life you old hag." I guess it's a good thing I'm not Rose, huh?
With all due respect, Your Majesty, I'm surprised you'd pay any attention to idle gossip. Surely it's beneath you? In telling me to break off with your great-nephew, you sound rather like a girl my age who heard rumors about her little sister and the off-limits bad boy in the senior class, confronting said little sister about it without even asking if it's true. I am fully aware of the fact that your great-nephew only wants me for sex, which is why I have not returned his affections and have no intention of doing so. As for talk of "men and drinking", I am a high-school student - I have dated boys and enjoyed alcoholic beverages at parties like any other girl my age. Furthermore, for the record, I am a virgin. If you don't believe me, you're more than welcome to have some royal doctor look into the matter; I assure you, the proof is there.
Regarding Christian Ozera, I myself shared your distaste and distrust for him initially, and even worked to keep him and Vasilisa apart. Having gotten to know him since then, while I don't love him, I do trust him with the princess. He is not inclined to turn Strigoi - he hates them, as, in a way, they took his parents from him. He was part of the group with me in Spokane who fought two Strigoi…perhaps you didn't hear this detail, but the Strigoi who captured us told us that whichever of the two Moroi with us - Christian Ozera or Mia Rinaldi - would be first to kill one of us dhampir and become Strigoi themselves would be allowed to live; the other four would not. Even after two days of starvation, however, Mr. Ozera refused to turn Strigoi. In the end, as part of a ploy, he actually had his fangs against my neck, and could easily have fed from me and killed me, but instead chose to free me from my bonds so we could escape. I know of no Moroi who is less inclined to turn Strigoi than Christian, and the only one I can think of who is equally likely is Mia Rinaldi, whose mother was killed in one of the recent Strigoi attacks - as I'm sure you're fully aware, Your Majesty.
Furthermore, Christian and Vasilisa are in love. They make each other very happy, I've seen it day in and day out. Being bound to Lissa as shadow-kissed Anna was to Saint Vladimir, I can attest that the bond they have is strong and true, and far from something that can be reasoned out of existence or dispersed by the disapproval of others - whether that disapproval is just or unjust. If I may be so bold as to confess something to Your Majesty that I've never admitted to anyone else, I envy their relationship, for the love they share and the joy they bring each other. Besides, surely Your Majesty, being far older and wiser and more experienced in such matters than myself, knows full well that love does not listen to reason? One cannot be forced to love someone. I was once loved by a cherished friend, and I tried to make myself love him - we were compatible in every way, and the most reasonable thing was for us to date; but I could not. A person cannot force themselves to love someone; for others to try to force love on someone is simply impossible. If you want Lissa to be with your great-nephew, you would have to force the marriage - and surely, Your Majesty would not force Princess Vasilisa Dragomir, the last of the Dragomir line, into a marriage to which she does not consent?
To be fully honest with you, Your Majesty - and I truly say this with all due respect - everything you have said to me during this entire conversation has quite frankly been ludicrous. Rather than waste time listening to gossip or micromanaging Lissa's love life, you ought to focus your time and energy on governing the Moroi population worldwide.