Can i fit a wider rear tyre on my honda cb shine dx?

I want to replace rear tyre (80/100/18) of my bike cb shine dx by a tyre size 100/80/18 without changing the rim. Is it possible? Will this change create any problem to bike?

There may not be enough room for the extra 20mm of width between the frame.

Get a measuring device, find the closest place your present tyre has now and add 10 mm.

Less precise handling.

Too wide for the rim
May be too wide for the space it has to operate in
Will definitely alter the handling, maybe in a big way too.