Troth/trɑːθ/ Definition 1 of 2Pro Tip 1/3Marriage Promise Primarily used in a historical or ceremonial context when someone promises to marry. In the days of yore, knights plighted their troth to ladies. Pro Tip 2/3Literary Usage More common in historical or literary texts, not used in everyday conversation. She read a novel where the hero plighted his troth to his beloved. Pro Tip 3/3Solemn Commitment It indicates a serious and formal commitment, not just a casual promise. When he gave his troth, everyone knew he would not waver.