single-hearted

"Through this election we will fully display the might of the single-hearted unity of our army and people," said Hyon Byong-chol, chairman of a preparatory committee for one of the sub-districts in the election.

From BBC ● Mar. 9, 2014

There never was a more honest or single-hearted judge than A. L. Smith, who was Master of the Rolls when the earliest cases came up for decision in the Court of Appeal.

From The Law and the Poor by Edward Abbott Parry

Utterly single-hearted, she lay there, brave and uncomplaining to the last, and seemed the only one unconscious of the pathos of her position.

From One Year Abroad by Blanche Willis Howard

All his free time and energy Spinoza dedicated with unusual single-hearted devotion to the disinterested development of a philosophy he knew would not be very acceptable to the general or even special philosophic reader.

From The Philosophy of Spinoza by Joseph Ratner

While, on the other hand, Aristides was so impartial and single-hearted that he got the name of Aristides the Just. 

From Aunt Charlotte's Stories of Greek History by Charlotte Mary Yonge