It is written [Shmos 19:3]: Moshe ascended to Hashem, and He to him from the mountain, saying, “So shall you say to the house of Yaakov and tell the sons of Israel.” Rashi cites from Chazal: So shall you say to the house of Yaakov: These are the women. Say it to them in a gentle language. And tell the sons of Israel: These are the males.
The commentators ask: Why did Hashem speak to the women before He spoke to the men?
The Beis Halevi answers based upon our Gemora, which stated that if one purchased a field from a man and then purchased (the lien) from his wife (in order that she should not collect her kesuvah from this field), his purchase is void, for we may assume that she only consented to please her husband. Although she does not truly want to sell her rights, she agrees to sell it in order to please her husband. This is why it is the custom by acquisitions to acquire it from the wife and then her husband. This way, we can be certain that she truly intends to sell it.
Accordingly, this is what Hashem wanted at the time the Torah was given. He wanted to ensure that the women will reveal their intent that they are truly interested in accepting the Torah without any trace of coercion at all. That is why the women were asked before the men. This way, their answer was actually their own. They were not accepting the Torah based upon their husbands desires; it was purely their own decision.