猫有九条命却只有一颗心
[māo yŏu jiŭ tiáo mìng què zhĭ yŏu yī kē xīn]
This means 'Cats have nine lives but only one heart', indicating the duality of a cat's resilience (as cats always land on their feet and hence have 9 lives) but having loyalty and affection limited just to one object or person.