Is the phrase "I have chosen my husband, and I have returned to you what you have entrusted to me" sufficient to revoke the continuous delegation that a man has given to his wife, and does the wife's intention have any bearing on this, or is merely uttering the phrase enough?

If a woman explicitly rejects the delegation with clear statements such as, "I have returned to you what you entrusted me with," then the delegation becomes void, and her intention at that point is irrelevant. Similarly, the delegation becomes void if the woman allows her husband to engage in intercourse or its preliminaries, even if she is unaware that doing so invalidates the delegation.