In HP and the Order of the Phoenix Dumbledore sends Hagrid and Maxime off on a mission to try to win the trust of the remaining giants. It seems that large amounts of enforced proximity and shared hardships has worked its [usual magic][1];

> ‘Madame Maxime went with you, then?’ Hermione interjected. ‘Yeah,
> tha’s righ’,’ said Hagrid, and a softened expression appeared on the
> few inches of face that were not obscured by beard or green steak.
> **‘Yeah, it was jus’ the pair of us. An’ I’ll tell yeh this, she’s not afraid of roughin’ it, Olympe. Yeh know, she’s a fine, well-dressed
> woman,** an’ knowin’ where we was goin’ I wondered ’ow she’d feel
> abou’ clamberin’ over boulders an’ sleepin’ in caves an’ tha’, bu’ she
> never complained once.’

Note also that much of her grumpiness in the HP:GoF seems to centre around her unwillingness to admit to being a giantess. By HP:OOtP it appears that she's come to admit (at least to Dumbledore and his close allies) that she has giant heritage.


  [1]: http://en.wikipedia.org/wiki/The_Proximity_Principle