be made of sterner / tougher stuff

/biː mˌeɪd ɒv stˈɜːnə tˈʌfə stˈʌf/

/biː mˌeɪd ʌv stˈɜːnɚ tˈʌfɚ stˈʌf/

to be made of sterner / tougher stuff

to have a stronger and more determined character or to be more resilient in the face of difficulty