。
Paul's hair has no sheen to it.
Literal
Paul [gen-の] hair [in-topic-には] moisture [subj-が] not-exist.
The composite particle には (に + は) topicalizes 'in / as for (Paul's hair),' followed by the existential frame ~がある/がない. Japanese frames 'has X / lacks X' as 'X exists / does not exist in Y' — a completely different grammatical shape from the English 'have' possessive. 潤い is the nominal form of 潤う 'to become moist,' an abstract noun for the quality of 'moistness / suppleness' applied here to hair.