charm the pants off someone idiom slang
（尤指初次见面）使…着迷，极讨…喜欢
to make someone like you very much, especially when that person meets you for the first time
"How did your sister's boyfriend get on with your mum?" "Oh, he charmed the pants off her." “你姐姐的男友跟你妈妈相处得怎么样?”“噢，他很讨她的欢心。”