Putnam's Phrase Book / An Aid to Social Letter Writing and to Ready and Effective Conversation, with Over 100 Model Social Letters and 6000 of the World's Best English Phrases

by Edwin Hamlin Carr

With an air of stolid desperation

With unflinching determination

Not to be tempted into foolhardiness

He held on with grim determination

With determined perseverance

Gently but firmly

A vigorous determination

With stoical fortitude

With all the energy of one’s soul

With redoubled energy