This is a poem about love.
First of all, the author wrote about Yue Lao, a fairy in myths and legends, who tied a red line to the destined person and made them fall in love. So those two sentences are: If Yue Lao knows that I miss him/her like the sea, please ask him to tie a red line of love for me. The last two sentences use Conan Meng's allusions to the effect that he has all kinds of ideas, but they are all illusory. Like a dream, he can only entrust this love to the sea, and no one understands it.