The line 'it occurred to me that Raymond would make a very fine runner' supports the theme that 'People can surprise the ones who love them.'
The line from the excerpt that best supports the theme that 'People can surprise the ones who love them' is 'it occurred to me that Raymond would make a very fine runner.'
This line shows the speaker's realization that Raymond, who they previously hadn't considered as a strong runner, actually has the potential to be a great athlete. It demonstrates that people can have hidden talents or abilities that may surprise those who love them.