What time will you definitely come/have come?

[Marika33]

Is A's response possible?

A: When/What time will you come?
B: I don't know for sure.
A: OK, when/what time will you definitely have come?

 

[emsr2d2]

No. In fact, A's first sentence isn't natural. In BrE, at least, we'd say "What time will you get here?" or "What time will you arrive?"

I'm not quite sure what A's response is supposed to mean. Are you trying to ask the person the latest time they will possibly arrive? If they're not sure exactly what time they'll arrive, you might be able to find out what the latest time is. If that's what you mean, the wording you've used doesn't work.

A: What time will you get here?
B: I'm not sure.
A: OK. Do you know what your latest possible arrival time is?