Please confirm me ?
I think do all in have opponent fold

If all opponents fold, you win.
The only way you cannot win is if you fold

there are many scenarios when you cannot win a hand in texas holdem poker.

1.) if you are bluffed out of a winning hand
2.) if you make a bad call
3.) if you fold the nuts.

when you play stupid hands you will always lose.

It is important to play according to hand strength and position, limping, checking too much will make it very hard to take down a hand.