Demoralize

[Sarah]

To corrupt or undermine in morals; to destroy or lessen theeffect of moral principles on; to render corrupt or untrustworthy inmorals, in discipline, in courage, spirit, etc.; to weaken in spiritor efficiency.The demoralizing example of profligate power and prosperous crime.Walsh.The vices of the nobility had demoralized the army. Bancroft.

[Ernesto]

To suck all hope out of someone or some group of people. As in ‘[Gareth Bale] came off the Real Mardrid bench to demoralize Liverpool in the Champions League final, scoring a [golazo] [bicycle kick] within two minutes of showing up on the pitch.’

[Vania]

Cause (someone) to lose confidence or hope; dispirit.