What do similar meditative concentration (samādhi) and similar non-arising forbearance mean? What is the non-arising dharma forbearance?

"Similar" means resembling or approximating, similar in form but not in spirit—something that is not real yet resembles the real. Similar samādhi has not yet reached the level of samādhi; it is close to samādhi, resembles samādhi, seems like samādhi, but is not true samādhi. Similarly, the similar patience with non-arising and the patience with the non-arising of dharmas have likewise not yet reached the level of the patience with non-arising and the patience with the non-arising of dharmas; they are merely similar to and approximate the patience with non-arising and the patience with the non-arising of dharmas, but are not the true patience with non-arising and the true patience with the non-arising of dharmas.

Once you clarify the noun concepts in the Chinese language, the general meaning of a sentence or a paragraph becomes clear. If you are not lazy in your thinking and are diligent in contemplation, gradually you will be able to comprehend some of the dharma meanings on your own. Always relying on others or on ready-made answers is a sign of unwillingness to think with care; this will not increase your wisdom. You must learn to rely on your own mental wisdom, the prerequisite of which is diligent cultivation of merit and meditative concentration (samādhi).