Just for the sake of instruction, I’ll assume that the problem read “assume that both stocks have an expected return of -1%”, and solve it anyways.
The stock with a lower standard deviation of returns has a mean return that is “further away” from zero in statistical terms (i.e. in terms of number of std deviations from zero). Therefore, the right-tail of its distribution (i.e. the area above zero) is larger. In other words, the probability of a return above zero (a positive return) is greater).
Since the total probability adds to one, this means that the probability of a negative return is smaller for the stock with a lower standard deviation.