
Even in a modern sense I think their behavior is way off. Tia is ignoring her fiance completely then goes into seclusion with visits of other men that she cares for. Then she takes a job that's obvious she doesnt intend to commit to the engagement. In a professional business gala you shouldn't have a public shouting match with your obvious enemy/competitor like she and her father did even if the Duke is in the wrong him self (a house who lost power and is called after tia and not before, to see the king). This reads more like a person whose never got into politics or work in corporate settings where there is current real world experiences of take downs with just rumors. Ha ha, we haven't improved much :)

I mean saying that she is there lover just for adding sugar in there tea before they asked is toooo much...no? And she doesn't want to be an empress and she knows how to act she was a woman that was trusted in her previous life and to add prince is one to be blamed for ignoring her even more (in previous life at least) and she know that if she wants different ending she must avoid him...and for me a person , a girl who is super open and close to most of her friends as much as to know (boys) which porn they prefer and be there bro that they tell almost everything it is really funny why rumours spread... The and sugar really?? Nothing better?

I feel you on that, I think it was just easy to point to the sugar incident because it shows just how close the MC is to them. She not only knows their preferences but also caters to them in a loving way. To her its friendship but to any other person that totally looks like intimate actions that a lover would go out of their way to do for the other. Though, I agree with not having better content to base the validity of this rumor, but like... cmon. Firstly Allen immeeeediately went to her place to propose when there was the tiniest possibility of her family splitting away from the imperial family and then Sein who should've kept his distance found himself visiting her everyday for no reason. So yeah, to others she is basically considered a married DC woman just not given the title or having gone through the ceremony yet. They're engaged and she is working to break that, but it's not official and no one knows but their parents >_>
So, I was thinking while reading the chapter that Tia is partly to blame for the rumors (please let me explain this concept before disliking).
We usually analyze this stories from a modern point of view. That means that to us titles, rich ceremonies and court stuff in general are strange, we don't feel comfortable with them and neither we like them when they regard the separation between classes since we believe in equality. In our opinion spreading rumors about Tia is wrong because they have no proof and they are just slandering her.
However, let's immerse for just a moment in a medieval or just nineteenth-century mentality.
Here we have that social classes are common and it is common knowledge to be respectful towards the ones who have a higher title than you. So the fact that Tia and her father don't take in consideration the duke's title is extremely disrespectful and out of place. It is normal for us, but we should contextualize it. We can't expect that changes happen in a night, even in our real history this mentality took centuries to be replaced with the modern ones.
Now, let's talk about the rumors.
Why did they spread? Because Tia had enemies. However it's not just for this cause, it is also due to how she behaved. If she hadn't let Allendis be so close to her in public these rumors would have probably taken more time to be regarded as true.
I know that "we shouldn't care about what others do and we shouldn't talk bad about them", but, again, think about it from a nineteenth-century (or previous) point of view.
She is going to be the empress, she is going to rule a country and she will have to have good relationships with the courtesans otherwise they could oppose her. For a ruler it is inconceivable not having his/her court's respect. She needs to prove them that she can be trusted and acting so close with a man who isn't her betrothed isn't a good starting point. Even in some modern society it's shameful for a woman and a man to be close.
Please, remember that I actually prefer (obviously) our modern views about this stuff, but I'd rather read the character's behaviors in a historical way because I think it is more accurate (even if it is stilla shojo) and that sometimes we should separate what's objective and what's subjective.
I just like analysis that aren't based simply on readers fast reaction, but on some deeper thoughts