He was a cold-hearted man, but his eyes filled with tears.
Literal
Cold-hearted man was [but-けれど], his [possessive-の] eyes [topic-は] tears [with-で] full became.
無情 = 'heartless, cold, unfeeling' — contrasts with 有情 ('sentient, feeling'). けれど ('but') is the slightly more formal counterpart of けど. 一杯 ('full') + になる = 'become full.' A poignant contrast between character and reaction.