noun

the quality of being faithful and dependable.

she did not think much of married bliss, yet she approved of constancy

fidelity,faithfulness,loyalty,trueness,commitment,dedication,devotion,dependability,reliability,trustworthiness,steadfastness,resolution,resoluteness,resolve,firmness,fixedness,steadiness,determination,perseverance,tenacity,doggedness,staunchness,application,staying power,obstinacy