1920x1080 is 16:9 ratio, so you're going to have bars left and right of your movie, if it's actually 1920x1080.if mine 30" monitor aspect ratio is 21:9, would i be able to get a full screen and watching movie if it's 1080p?
But some releases are not, they're 1920 wide but less than 1080 high, because they're released in a wider ratio. If you have a release like this (and it doesn't have encoded black bars top and bottom) it would fit your screen better.