Moreover, her son was right, he was honest by nature, and it would be better to marry a woman with a gentle disposition who wouldn't despise him for continuing to fail the exams.
Madam Wang didn't want her son to marry an overly ambitious wife; she simply wished for a daughter-in-law who could peacefully care for her son, not use him as a bragging asset.
Ah Zhang was willing to study hard because he enjoyed it, and he had indeed made an effort, so becoming a scholar was already quite an achievement. As for future success, both she and Chu Cai didn't press for it; you could say they didn't pressure Chu Zhang. She just wanted Ah Zhang to be happy.
At the very least, with Ah Zhang's status as a scholar, his future life would be comfortable, so whether he continued his studies or not, both Madam Wang and Chu Cai wouldn't intervene.