你的姓是什么/ 用英语怎么说

would you pls let me know you familiy name/surname?

Can I have your family name?

这样的说法更婉转一些

may i have your family name?
这种说法比较客气
family name 是姓的意思

What is your name

what is your surname?
Could I know your surname?

What's your last/family/sur name?