Fantasy YA trilogy printed in one book from the 90s with a purple cover and castle on the front

Question

I'm looking for a book I believe I read in middle school, which would have been 1999-2002.

I wish I could recall anything about the characters other than I'm fairly certain it's told from a female POV. I can't recall if she's a princess or assassin or just a normal person, but I feel like there was a magic element to the story. The book I had was a trilogy printed within one whole book. I recall the cover being purple and it might have had a castle on it? And it might have been my first ever introduction to "enemies to lovers" lol in that I think I recall the female main character and male main character not liking each other at first, but then falling in love. I also believe something happened that separated them and she maybe had to save him?

This is so bad and I am so sorry, I've just thought about it so much for two decades and figured it couldn't hurt to put it to the Internet to try to find it. I've hunted popular fantasy/YA books on lists and scoured hundreds of pictures of book titles to no avail.

Answer 1

The omnibus collection of Meredith Ann Pierce's Darkangel Trilogy?

The cover, while lacking a castle,is grey and purple, and the plot fits. The female main character, Aeriel, is kidnapped by the vampiric titular Darkangel and taken to his castle to care for his wives, and they eventually fall in love, spend time apart, and are reunited. He is saved multiple times by her (most notably at the climax of the first book).