can't you be sweet with me?
when somebody teases you, or misjudges you, or says things that aren't pleasant, ...then I want to say there is nothing else u can do but being bitter. Can you be sweet at all with me?
Sorry bahaar not exactly sure on your question here, but the way that you would say the title in general would be;
"can't you be sweet to me?"
Indicating the action of being sweet being something that can transcend to others. Such as;
"can you be sweet to him/her/them please" "he is being sweet to her"
hope that's a little clearer.