Overall, this is a story that knows how to write adults. Better yet, romance between adults. While there's a well-done plot beyond romance, the story itself is just as it's titled: the Villainess is, indeed, in Love. With a little help of the convenient worldbuilding wherein the two's inner natures - water and fire - balance the other out and, in safer words, their chemistry is perfect. FL was isekai'd into the story as the villain who vied for her best friend's man, but a year prior so none of the story itself truly began. So in order to avoid becoming such a character, FLdoes her best to become her own person and allow the two leads to fall in love with the other. Unfortunately, she can't hold her liquor and incidentally was the one the ML chose.

Over the course of the story, the cast evolves and moves the story along. FL is able to overcome her fears and fix anything she unintentionally messed-up along the way when she isekai'd and freaked-out, and ML overcomes his past and comes to heal. The two are a happy, healthy as a couple that encourage the other every step of the way.