I see that your books are in Turkish which makes it difficult. I assume she reads English too, though?
If so (or even if not), you could go much more subtle. As a Tolkien fan, I have always coveted this edition of The Hobbit. It's just so nicely and minimally designed... tiny, leatherbound, gilt page edges... it's gorgeous just as an object. A simple little gift which is also total class. I wish they'd do the LoTR and Silmarillion like this.
Link: https://www.amazon.com/Hobbit-Deluxe-Pocket-J-R-R-Tolkien/dp/0544045521
And here is the 4 book set (with a slightly different version of The Hobbit book): https://www.barnesandnoble.com/w/the-hobbit-and-the-lord-of-the-rings-jrr-tolkien/1119268896?ean=9780544445789&st=PLA&sid=BNB_New+Core+Shopping+Textbooks&sourceId=PLAGoNA&dpid=tdtve346c&2sid=Google_c&gclid=EAIaIQobChMIp-796...
https://www.amazon.es/dp/0544045521/ (change the .es for whatever and it should work) This is the one I got, although the reviews as usual are from 6283 different editions... I saw it in a video by sheer luck looking for a LOTR edition, the Amazon pics don't do justice. Here have it https://youtu.be/OS7L1xhTW4Y
The version in the box set with The Lord of the Rings and the individual The Hobbit are different. Here it is on Amazon.