孤独成性只因厌世之心
[gū dú chéng xìng zhĭ yīn yàn shì zhī xīn]
The phrase '孤独成性只因厌世之心' translates to 'Loneliness has become my habit because of my disillusionment with the world'. It expresses profound alienation, possibly stemming from negative experiences or views towards society and people around them.