若 is a pictographic character. The oracle bone script --new/048ruo/%5B2%5Djin(1).gif?resize=14%2C23){kind=small}
depicts a woman tidying her hair with both hands, indicating that a woman is meek and obedient.
In the bronze inscription --new/048ruo/%5B2%5Djin(2).gif?resize=14%2C23){kind=small}
a --new/048ruo/%5B2%5Djin(2)jian(1).gif?resize=9%2C14){kind=small}
is added to emphasize the meaning of “agreement or positive response”.
When the meaning of “agreement or positive response” for 若 got obsolete, a new character 喏 was invented to express the same meaning.