diacritics not shown properly

[paravyoma]

Hello all,
I try to make a docx fil into AZW3. The file has kind of special letters with diacritcs. You can find a sample in the attachment. Simply saying, these are sanskrit tranliteration letters. It means normal latinic letters with a dot or line above/below it.
I made a conversion of a file and in Calibre e-book viewer the letters are shown properly. But when a book is transfered and opened in Kindle, the letters are just a mess.

Please, can you help me work this out.

If you need any more information regarding the problem, please say it.
Also, sorry, I am quiet ignorant of these topics and maybe my post is not properly expressed.
Thank you very much