What did this mean?

What accident was causing this new change of feeling in this April day of a girl?

But when her sparkling blue eyes gazed at him so brightly and at the same time so plainly showed that she knew she had wronged him, he clasped the hand, and his face again wore a friendly expression.

Then Barbara laughed in her bewitching, bell-like tones and, like a naughty child begging forgiveness for a trivial fault, asked him gaily not to take offence at her foolish arrogance.  All the new things here had somewhat turned her silly brain.  She knew how faithfully he served her Charles, and for that reason she could not help liking him already.

“If you have any cause to find fault with me,” she concluded merrily, “out with it honestly.”  Then addressing Frau Lerch, not as though she were speaking to a servant, but to an older friend, she asked her to leave her alone with Herr Adrian a short time; but she insisted positively on having her own way when the dressmaker remarked that she did not know why, after the greatest secret of all had been forced upon her, her discretion should be distrusted.

As soon as she had retired the valet entreated Barbara to beware of the advice of this woman, whose designs he saw perfectly.  He, Adrian, would wish her to have a companion of nobler nature and more delicate perceptions.

But this warning seemed scarcely endurable to Barbara.  Although she did not fly into a passion again, she asked in an irritated tone whether Adrian had been granted the power of looking into another’s soul.  What she perceived with absolute certainty in Frau Lerch, who, as her dead mother’s maid, had tended her as a child, was great faithfulness and secrecy and the most skilful hands.  Still, she promised to remember his well-meant counsel.

Adrian’s warning always to consider what a position her lord occupied in the world, and to beware of crossing the border line which separated the monarch from his subjects, and even from those who were of the highest rank and dearest to him, was gratefully received, for she remembered the sharp rebuff which she had already experienced from her lover.  It proved this excellent man’s good will toward her, and her eyes fairly hung upon his lips as he informed her of some of his master’s habits and peculiarities which she must regard.  He warned her, with special earnestness, not to allow herself to be used by others to win favour or pardon for themselves or their kindred.  She might perhaps find means for it later; now she would at once awaken in the extremely suspicious monarch doubt of her unselfishness.