The Dutchman, smiling and looking relaxed after arriving from his stint as Netherlands manager at the World Cup, also made it clear that the commercial demands at United would make his job harder.
"I'm now two days here," Van Gaal, 62, told reporters. "I've met a lot of people, and when you see that kind of people loving the club they expect a lot of me.
"Can I fulfil that expectation I think I can, but because of the greatness of this club it is much more difficult than in another club.
"This club is also guided in a commercial way and we have to fulfil that also, but it is not always possible to fulfil both.
"I will do my utmost best. That's what I can give. I cannot give predictions."
Van Gaal added: "I cannot give predictions because you never know. It's the biggest club in the world. Within two days I know already how important Manchester United is but also how important the sponsors are.
"I have to adapt to this big club. It will not be easy but you can see what I have won."