Jinshi definitely likes her a /lot/, in the romantic sense but also in the broader sense - whether you'd call it /love/ is hard to say, given his position and character, but by the second half of the LN story (vol 5-6 and onwards) it's pretty clear he wants her as his "lifetime companion".
Mao Mao is just so totally . . . guarded is the word that came to mind first, but it's not really the right idea. Self possessed, maybe? I think the frog incident may be the only time in the whole story so far where she's genuinely freaked out, which even includes a couple of times where she was moments away from death - she just never loses her self-control and self-possession, there's /always/ something in the back of her mind running calculations about what the best thing to do next is. It's understandable given her family background - the La/Ra clan (can't remember which way the translators here went) seems to just be built that way, which makes them extremely formidable, but also extremely difficult as people. For all that she barely acknowledges her relationship with her biological father, she's /absolutely/ typical of that family. Which is probably one of the reasons why people in the know (all the way up to the Emperor) treat her the way they do - they see the enormous value that her particular talents can bring, combined with that familial tendency to be totally predictable (even in their unpredictability) and reliable (even in their unreliability). And she takes after her adoptive father far more than her biological father, which is a great help there . . .
All of which makes it really /really/ hard to judge how she feels about things. Particularly squishy emotional stuff like this "love" thing. And even more particularly when you consider how she grew up, and her experience with her biological parents. Growing up in the red light district meant that she has an almost perfect understanding of all the physical aspects of "love", but her understanding of the emotional side is far more limited. Her earliest experience is her parents - Lakan is completely bonkers, but he was /utterly/ in love with Mao Mao's mother, even if he totally f*cked up that relationship; her mother was . . . well, we don't get a lot of information about her, but she was clearly an unusual person even before she got sick, as well as being a high end courtesan. And as Mao Mao has grown and seen more of the various forms and ways of love she's seen most of the /worst/ aspects at the same time as the good aspects - the bit of her that's always running calculations is taking /all/ of that into consideration, along with all the other things going on (particularly with Jinshi and all /his/ mess), which makes it almost impossible for her just be a normal human being who's fallen in love. Her response to being poisoned is . . . atypical, to say the least; her response to someone trying to kill her is just as atypical; it makes sense that her response to feelings of physical and emotional attraction would be pretty atypical, too.
So yeah, "romance" isn't really what's happening here, even from Jinshi's side (though his side of their relationship is a lot more easily recognisable). But I don't think it's really fair to say that there's nothing akin to romance from Mao Mao's side - I think Jinshi is by /far/ the closest she's ever come to falling in love in the more normal sense, and I think the way she feels about him is actually a realy good match for the way he feels about her, particularly as she finally starts giving up her attempts to avoid letting him trap her into being his wife/partner/whatever the hell they end up being.
This isn't exactly a Mills and Boon (it's actually closer to Austen in its handling of romance - just don't tell any English Lit majors I said that, I'd rather not be lynched!), but I do think a romance tag is justified.
