There was one thing that she did not see; one point of view in which the matter had not been presented to her.

The cause for her sacrifice had been made plain to her, but why was the sacrifice of the other also to become necessary?
By not yielding she might be able to keep her lover to herself; but if she were to be induced to abandon him -- for his sake, so that he might not be ruined by his love for her-- why, in that case, should he not take the other girl for his wife?
In such a case Nina told herself that there would be no world left for her.

There would be nothing left for her beyond the accomplishment of Lotta Luxa's prophecy.

But yet, though she thought of this, though in her misery she half resolved that she would give up Anton, and not exact from Rebecca the oath which the Jewess had tendered, still, in spite of that feeling, the dread of a rival's success helped to make her feel that she could never bring herself to yield.
"Shall it be as I say ?" said Rebecca; "and shall we, dear, be friends while we live ?" "No," said Nina, suddenly.
"You cannot bring yourself to do so much for the man you love ?" "No, I cannot.

Could you throw yourself from the bridge into the Moldau, and drown yourself ?" "Yes," said Rebecca, "I could.