。
Don't trust people who praise you to your face.
Literal
Front [at-で] people [object-を] praise kind [possessive-の] person [object-を] trust-[prohibition-な].
Another bit of cautionary folk wisdom. ~な attached to a dictionary-form verb is the bare negative imperative — 'don't X.' Curter and rougher than ~ないでください. The relative clause 人を誉めるような人 ('a person who is the sort to praise people') uses ~ような to characterise a type — 'the sort of person who.'