。
Let's meet at 3 tomorrow.
Literal
Tomorrow 3-o'clock [at-に] you [dative-に] honorable-meet let's.
Note how 会う takes に for its object (あなたに) — even in keigo. お会いしましょう stacks the humble pattern onto the volitional for a polite-invitation feel.
。
Let's meet at 3 tomorrow.