Found a magazine article that was published way back when the Hayate no Gotoku!! DVDs were launched in Japan. Rie Tanaka, the seiyuu for Maria, was asked several questions regarding Hayate and his relationship with the girls in the show, especially Maria.
Regarding Maria’s feeling towards Hayate, she feels Maria herself still doesn’t quite know whether she has feelings for Hayate. However, if her feelings does develop that way, what will become of her relationship with Nagi, she wonders.
Asked about what kind of advice she would give to Maria, Rie says that Maria should just be honest with herself. Until now, Maria is more like an older sister and senior figure to Hayate. On the other hand, when that happens, she would feel sad for Nagi.
The most interesting part is when she explains what she thinks generally happen when people consult other people about their love problem, like the Hinagiku scene in the story. In the end, the one who decides is oneself, so she thinks people generally have already decided anyway. Love consultation just makes you feel more at ease with the decision.
Images found at animage.