In meetings with investors in recent weeks, Comcast Corp.’s chief executive officer has made it clear he wants 21st Century Fox Inc.’s entertainment assets and will spare nothing to beat Walt Disney Co.’s $71.3 billion offer. With Fox shareholders scheduled to vote July 27 on Disney’s bid, a deadline looms. Comcast, the largest U.S. cable provider, has been mulling next steps, including a possible partnership with private-equity firms, to compete with Disney. The company needs to sweeten its $65 billion all-cash offer enough to win over Rupert Murdoch and his family, the largest shareholders of New York-based Fox.