In Darkness by L. Diane Wolfe

Souls shrouded in darkness...

Abducted from her research station, Liz's life is flung into chaos. Sold into servanthood for her knowledge of planetary mining to a race called the Stren, she discovers her problems go far deeper. She is to marry her alien master, Krist, after enduring a procedure designed to eradicate her emotions.

Desperate, Liz persuades the Stren to grant her the duration of a short voyage to change his perception of emotions. But how can she convince someone lacking feelings of their value? Is there a means of accessing the emotional side of Krist?