Unrequited Love Is a Long, Long River

A light description of a strong secret love. Suddenly I remembered a saying: Secret love is a wonderful pantomime, but if it is spoken, it will turn into a tragedy.

I don't know the origin of the love, so I agree with it very much. But suddenly I thought of the four words immediately following this sentence: go deeper and deeper. Author's reply: Yes.

I don't understand it a bit Author's reply: What don't you understand?