Can someone translate this sentence from the finnish matriculation exam?

This was a part of the english matriculation exam in Finland we had a few days ago. I did really well in the exam, but there was this one sentence that just went completely over my head. Numbers 3) and 4) mark the choices from which you had to pick the correct one.

Context: It’s commonly thought that for centuries people didn’t smile in pictures because their teeth were awful. This is not true – bad teeth were so common that this was not seen as necessarily detracting from a person’s attractiveness. (This is the sentence) Lord Palmerston, the then prime minister, was described as being devastatingly good-looking, despite his having 3) a number of / an amount of / an account of / a display of good reasons 4) for being disinclined / be disinclined / but be disinclined / being disinclined to encourage a smile.

I did choose the correct ones (a number of and for being disinclined) because they made the most sense, but that still left me scratching my head, so I was hoping someone from here could maybe explain to me what the sentence means. Thanks !