Tā pāi zhe xiōngpú bǎozhèng yídìng wánchéng rènwu.
He slapped his chest and promised he would definitely finish the job.
Tips
mistakes
Two readings, two words. This one, pú, is the chest, the reading you need for 胸脯 and 鸡脯肉. Read fǔ, the same character means dried meat or candied fruit, as in 肉脯 and 果脯. Saying xiōngfǔ for the chest is the usual slip.
usage
Chest gestures carry set meanings. 拍胸脯, to slap your chest, is how you say you personally guarantee something, and 挺起胸脯 pictures standing tall and proud. In cooking, 鸡脯肉 is the chicken breast fillet.
Left meat-flesh radical, the side form of 肉, visually the same as 月 but a different semantic source. It is the indexing radical, and under this reading it points straight at body flesh: the chest wall in 胸脯 and the breast fillet in 鸡脯肉.
Right 甫 supplies the sound. It matches the fǔ reading exactly, and pú keeps the same phonetic shell with a shifted initial. Same family: 捕 catch, 哺 feed, 浦 riverbank, 圃 garden.