The word she uses, "alurlssrin", is specifically a word used by the faithful of Eilistraee, as an expression of their faith. Eilistraee is a drow goddess who is opposed to Lolth, and who leads her faithful to live on the surface in the light, in harmony with other races, which goes against Lolth's teachings.
It's very strange for Minthara, a Lolthsworn drow, to use a word like this, right? Eilistraee goes against everything she ought to stand for. My friend pointed this out in disappointment, as to her it's another example of Minthara's character writing having a lot less care put into it.
I'm not that well versed in drow lore yet, I'm still learning about it (inspired by Minthy :D), but I know Minthara isn't following Lolth anymore despite having the tag in the game, so after giving it some thought I think this might be another case of display of how
she learns to allow herself to love and feel things freely and be more herself without the restraints Lolth and by extension Lolthsworn drow society placed on her previously, since her whole romance arc is focused on her learning love and trust for what i believe is the first times in her life that she can do that without fear, and looking at other drow words for love, it seems that "alurlssrin" explains what she's feeling the best, since it is a deep love and not a fleeting one or lust
As an aside: I've tried to post this three times throughout my day, and each time I click "post", the forum stops working.

also I felt this, yesterday the forum was unresponsive almost the entire day for me :')