Boromir- the first to become corrupted.

[MLD-Grounds-Keeper-Willie]

Boromir was stubborn. He refused to take the advice of the wise, who told him of the dangers of the ring. He refused to acknowledge the dangers of the ring. So his ignrance (refusal to comprehend the advice meaning he was not knowing of the dangers) led to his corruption.

was so worried about his city and his people

That's what kept him from understanding the dangers and using their advice.