She will weigh him down like a heavy testing stone: The reference here seems to be to a heavy stone that someone might try to lift to prove his strength (compare Zech 12.3). When it is said that Wisdom weighs a person down, the meaning is that Wisdom’s demands, her requirements, are heavy (so Good News Translation).

He will not be slow to cast her off means that the person with no determination will quickly give up the search for Wisdom.

Good News Translation dispenses with the image of the stone (translating “burden”), but it lacks the idea of testing. This could be introduced without too many extra words by rendering the whole verse as follows:

• Her requirements are a burden heavier than they are willing to bear, and since they cannot carry them, they quickly lay them aside.

For languages that cannot personify Wisdom, translators may say:

• The requirements for people to become wise are like a burden that is so heavy that they are unwilling to bear them. And since they cannot follow them, they quickly lay them aside.

Contemporary English Version reorders the clauses of the verse as follows:

• When Wisdom tests them,
they will toss her aside,
as if she were a stone
too heavy to carry.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Sirach. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here.