甘あまい物ものは別べつ腹ばら

Meanings

1

there's always room for dessert

Proverb used when someone claims to be full but still has appetite for sweets. Literally 'sweet things go in a separate stomach'.

「もうお腹なかいっぱい」と言いいながら、ケーキを見みると「甘あまい物ものは別べつ腹ばら」と言いって食たべ始はじめた。
Even after saying 'I'm full,' when she saw the cake she said 'there's always room for dessert' and started eating.