I read this book a few years ago cca 2013-14, can't remember the name or author, sadly. It was about an alien that comes to earth as ambassador and looking for his mate, which he would find when feeling a particular warmth/tingling in his spine.
She is a young and clumsy secretary of the staff of the president of the US. The alien prince recognizes her as his mate and makes a beautiful garden close to her apartment for her, on an earth where flowers are very rare, brings her visit his home planet where she is kidnapped by other aliens and brought to be sold on a far away planet.
She is saved by another alien people, the strongest ones yet in the story and it appears that the heroine is the daughter of the alien queen who left her on earth with adoptive family to protect her from some menace. Finally it ends all well. Book is quite well written and has some good humor. Thank you for all help.