The second line is about enduring everything that is difficult, enduring sorrow and joy by oneself, others are difficult for me, knowing one's warmth and coldness, falling apart quietly, and healing silently.
The following is a relevant introduction to couplets:
Couplets, also known as couplets, door pairs, spring stickers, spring couplets, couplets, couplets, etc., are written on paper, cloth or carved Dual sentences on bamboo, wood, pillars. Couplets are neatly contrasted and harmonious, and are a unique Chinese art form that uses one word for one sound. Couplets are treasures of Chinese traditional culture.
Couplets are also called antithetical couplets, door pairs, spring stickers, spring couplets, antithetical couplets, peach charms, couplets (named after the couplets that were often hung in the halls and halls of houses in ancient times), etc. It is a kind of antithetical couplet. Literature is said to have originated from Taofu. Another source is spring couplets. The ancients often posted the word "Yichun" on the first day of spring. Later, they gradually developed into spring couplets, which express the Chinese working people's good wishes to ward off evil spirits, eliminate disasters, and welcome good fortune.
Parallel prose and rhymed poetry are the two direct sources of couplets. In the process of its own development, couplets also absorbed the characteristics of ancient poetry, prose, lyrics and music.
The above information refers to Baidu Encyclopedia - Couplet