to cross one's fingersUsed to express hope that something will go well or to wish someone good luck. It is often used in expressions such as «je croise les doigts» or «on croise les doigts», but the infinitive form «croiser les doigts» can also be used directly.
FR: Pour que tout se passe bien, il faut croiser les doigts !
EN: To make sure everything goes well, we have to keep our fingers crossed!