In ‘An Unexpected Journey’ Bilbo can’t kill Gollum. He pities him, and even though he wanted to at one point, he couldn’t go through with it and kill him.
But, not long after that, we see Bilbo kill for what is quite likely the first time. He kills an orc, for Thorin, and even though he knows pretty much nothing about fighting, he still tries to go after Azog when the orc and his warg get too close to Thorin.
I’m not the best with subtext, but isn’t there a saying ‘I’d die for you/I’d kill for you’? Just saying, the ship pretty much sails itself.