constancy
US /ˈkɑːn.stən.si/
UK /ˈkɑːn.stən.si/

1.
忠诚, 坚定, 不变
the quality of being unchanging or steadfast; faithfulness
:
•
Her constancy in friendship was admirable.
她在友谊中的忠诚令人钦佩。
•
The constancy of the stars in the night sky is a comforting thought.
夜空中星星的恒定是一种令人欣慰的想法。