11 Feb So it sounds very much like the young adult fantasy book From Several Thoughts by the Carol Matas and you will Perry Nodelman
Old sis initiate dating pal's aunt
The two children with mind powers are Lenora, a headstrong princess who can make anything she imagines real, and Coren, a shy prince from a kingdom where everyone can read each other's thoughts. The two are betrothed by their parents, the rulers of neighboring kingdoms (both made-up places). They are kidnapped and taken to a strange country where their normal powers are gone. Together, they have to defeat the evil tyrant Hevak and save both of their kingdoms. Originally published in 1995, I read this in the late 1990's too, when it was published as a Point Fantasy paperback. The cover is dark, with a picture of Lenora right-side up in the lower right corner, and Coren upside-down in the upper left corner. There are also a few sequels, called More Minds , Out of Their Minds , and A Meeting of Minds . Pamela Service, Being of Two Minds , 1991, copyright. Except for the dates, the details match Being of Two Minds by Pamela Service . The two characters that could get into each other's mind were an American girl and a crown prince of a small kingdom.