一次生，两次熟 (一次生，兩次熟) yīcì shēng, liǎng cì shú

yīcì shēng, liǎng cì shú phrase unfamiliar at first but you get used to it; strangers are first meeting, but soon friends
Domain: Modern Chinese 现代汉语
Notes: (CC-CEDICT '一次生，兩次熟')