Guardiola has been unable to sustain a Premier League title challenge in his first season as City manager while his side's Champions League campaign ended at the last-16 stage.
The Spaniard has been pleased with some aspects of City's progress, as they face Arsenal in the FA Cup semi-finals this weekend, but he knows he is being judged by much higher standards.
Last season Guardiola's predecessor Manuel Pellegrini won the League Cup, finished fourth in the Premier League and reached the Champions League semi-finals, which club bosses rated as a disappointing year.
Guardiola said: "I don't think they will be happy. The expectations of the club are as high as possible and are to win the titles that are on the table.
"So if they are not happy I can completely understand. We could have done better in terms of the results and even in the way we played because we wanted to be in the race for the title and in the Champions League until the end.
"Despite the fact that I am happy with what we've done, it is still not enough."
City and Guardiola were criticised after last month's Champions League loss to Monaco, when they went out on away goals after losing the second leg in the principality 3-1.
Guardiola feels, at least, the response to that dispiriting loss - they had gone into the game with a 5-3 aggregate lead - has been positive.
City played out a pulsating 1-1 draw with Liverpool in their first outing after the defeat before decent performances, even though they did not win, in testing back-to-back fixtures against Arsenal and Chelsea.
He said: "This is a fantastic club, a fantastic team. I'm so proud of them, especially in the bad moments like how we overcame our defeat in the Champions League against Liverpool.
"The people cannot imagine when you are out of the Champions League, to play Liverpool just three days later, who have had a week of rest, 1-0 down, how we played that game.
"That is how I want to see my team. We went to London to play Arsenal and in the first half we played as well as we have all season."