"... no solo por su físico, sino también por su personalidad ..." >
> Indeed, my Grammar book (by Butt and Benjamin) actually mentions that "sino" is particularly common after a "No sólo ..." construction; [with a bit of luck, I will remember that in future!]
So, it might be worth adding that^ to your " Difference between pero, sino and sino que in Spanish (but) " ... [together with an example]?
You might also decide to add the above grammar-lesson to the guidelines, notes and hints relevant to this exercise? ... As you say, it is a case of two possible different translations of "but", so English people need to think about it carefully.
