Answer:
Bitter
Step-by-step explanation:
According to the excerpt from act 2, scene 1, of Julius Caesar, Portia says she would not let Brutus "eat or sleep" until he has told her the source of his grief. She is unhappy when he tells her that he is only unwell and nothing else is causing him grief.
Therefore, according to the excerpt, the tone Portia uses when speaking to Brutus is one of bitterness.