Have you tested the paint? Only way to know how it will look in your space. Buy or make some larger sample boards and move them around the room at different times of day.

it's kind of hard for me to do, practically. I am buying this apartment, don't yet have full access to it, and need to make that decision very soon. There is nothing special or unique about this situation. We are repainting the whole apartment. The 2 bedrooms I mentioned have window air conditioners and the windows aren't that large - regular size.

It will look good. It’s a good white everywhere.

You have lights, right? Turn them on, then make a decision about the color.