我想我不够成熟我想我不够好
[wŏ xiăng wŏ bù gòu chéng shú wŏ xiăng wŏ bù gòu hăo]
Translated into 'I think I'm not mature enough; I think I'm not good enough,' conveying feelings of inadequacy and lack of confidence, perhaps in a relationship or about themselves in general.