Then bring with you another girl (one that you could hire as a tempo girlfriend), 30 minutes before, and act sweet with each other.

When the girl comes and sees you with another woman....she leaves.

Though depending on the length of relationship and how close she is to you, you might expect a scene in the Restaurant.

If she has no problem with it, then be very happy (3-some) or be very suspicious (she might also have another boyfriend).