This is why fanboys ruin fanbases. His quote was a bluff to entice Kuma into killing him instead of Zoro or Luffy, the same way Zoro had done to try and save Luffy.
Imagine knowing that Sanji is going to be part of the crew that’s led by the man who will become the Pirate King, who invaded all three Marine strongholds, declared war on the world government, and struck one of the highest figures in the World Government, broke up the execution of one of the worlds most notorious criminals, and plunged the New World into chaos by challenging two of the Yonko, and suggesting that his words were more than bluster and that Sanji is going to be the most trouble for the marines.
Ridiculous.