SOLVED. Fantasy with two worlds [s]

[Ahasver]

I have read this when I was a teenager, so it was published prior to 2000 - I can only remember magic being present, magical transportations from one world to another, being in a bedroom and maybe there was a horse race or some other race. Whenever I think of it the word Apprentice comes to mind, but whenever I try to read Raymond Feist's Magician/Apprentice it does not ring a bell (it does not help that I read it in different language).
Does anyone have any tips? Thank you!

[Carly Lenhardt]

I don’t know, but it sounds kinda like The Scorpio Races. I haven’t read it yet though.

[Kris]

The Scorpio Races by Maggie Stiefvater - carlyslibrary_'s suggestion

[Lou]

Deep Secret? it has travel between worlds (starting within a motel room in one case), searching for an apprentice, and centaurs.

[Angela]

If you think it is Raymond Feist, could it be Faerie Tale? If you think it has the word Apprentice in it w/ those remembered details, perhaps something from Piers Anthony's Apprentice Adept series.

[Ahasver]

Hi all! Thank you a lot and sorry for not responding sooner - for whichever reason, I did not get a notification on this.
However, Angela, you are a miracle worker - it is Piers Anthony's Split Infinity. Unbelievable.
Thank you also for other tips - I will definitely check them out and read :)

Have a great day, you just made mine!

[Angela]

YAY!! :)

[Kris]

Glad you found your book, Ahasver. Here's the link - Split Infinity by Piers Anthony.