What is the ruling on someone who opened a store and pledged to donate 10% of its annual profit, but then did not donate anything due to low income, and because the store started with a small amount and then his wife's money was added to buy merchandise, and the store barely covers household expenses?

The shop owner is not obligated to allocate a percentage of his shop's earnings unless he has made a vow to do so. The mere statement, "I will allocate 10% of the shop's earnings annually," is not considered a vow unless accompanied by the intention of making a vow. This differs from saying, "For Allah's sake, I am bound to allocate 10%," as this is an explicit vow that does not require an intention.