Meaning of "I filled a river, and now all thoughts are sacred and pure" in Kung Fu Hustle

The full exchange from the scene @ 38:00 (English dub, Region 1 DVD) is as follows:

BONE

Where have you been?

SING

I don't really know.

BONE

Huh? Maybe it's better that way. Memories can be terribly painful. Being able to forget is a great blessing.

SING

That's quite deep. You seem to have learned a lot.

BONE

All the sorrows I've had to endure (pause) have filled a river, and now all thoughts are sacred and pure.

The subtitles for the same scene (English sub, Region 1 DVD) (script here) are as follows:

BONE

Which hospital did you go to?

SING

Don't remember.

BONE

Maybe it's better that way. Memories can be painful. To forget may be a blessing.

SING

I never knew you were so deep.

BONE

All the sadness one can bear... down the river everywhere.

Before the context of the pretty woman, Bone is waxing philosophical about Sing's inability to remember how he recovered from his injuries (or maybe how he was injured). In the dub Bone seems to speak from experience, as if he himself has accumulated a river's worth of pain and let it all go, and is enlightened as a result. In the sub he seems to just be quoting a proverb*.

Of course, the words are superficial and humorous as they 1) are against type (Bone the simpleton is incapable of accumulating anything but weight and has no business spouting proverbs) and 2) contrast with the action (whatever significance the conversation has, it's derailed by desire when the pretty woman walks by).

Bone trails off before finishing his proverb in a way which may also be going for laughs. The proverb ends in a trite rhyme (sub) and it's hypocritical of him to be talking of things "sacred and pure" when he's clearly indulging his lust (dub). Both of these may be a result of distraction staring at the woman.

I'd say the actual meaning of the words are no more complex than an equivalent scene in an American comedy where, for example, two guys are distracted and the conversation ends in a Freudian slip, or conventional advice becomes a double ententre ("Like they say, the tighter you wind..." (both stare at woman) "...the bigger you sproing.") Good advice cheapened by shallow behavior is an easy way to add false complexity to a scene and enhance the overall humor. On closer examination it has little depth.

A bit of an obsessive deconstruction but that's my take. Whether any of it is actually funny is beyond the scope of this reply. :)

*: I can't find any instance of this proverb outside of Kung Fu Hustle.