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Fumio is honest, so everyone likes him.
Literal
Fumio [topic-は] honest so everyone he [subject-が] likes.
A clean example of ~から/だから reasoning: 正直だから (because he's honest). 皆彼が好きだ shows the pattern 'everyone likes him' where 彼 is marked by が as the object of the emotion 好き — in Japanese, the liked person takes が, not を.