If you are in check you MUST do something about it before doing any other move. If you can't do anything, it's checkmate. So your opponent couldn't checkmate you, he wasn't allowed to.
Otherwise, hypothetically, on the next move white takes black's king and wins, before black can take the white king.
Hi, i just confused with Check and Checkmate, please go to move 23, if i take enemy bishop it gives check state while in opponent turn, he will take my rook so checkmate. Since my opponent didnt take that move, im curious to know about it. Suppose if the opponent use that move? white will lose? ignoring check state in black? or taking the rook is forbidden?