、。
We're hoping he'll show up Saturday afternoon.
Literal
We [topic-は], he [subject-が] Saturday [attributive-の] afternoon figure [object-を] show [nominalizer-の]-[object-を] hope-for-[state-ている].
姿を見せる ('to show one's figure' = 'to appear, show up, make an appearance') is an idiomatic expression common in both casual and formal Japanese. 期待する ('to expect, hope for, look forward to') takes a nominalized clause as its object. The embedded subject 彼 is marked with が since it's inside a subordinate clause.