разочаровать означает в английский

underwhelm [underwhelmed, underwhelming, underwhelms]▼(fail to impress)
verb
[UK: ˌʌndəwˈelm] [US: ˌʌndɚwˈelm]

disappoint [disappointed, disappointing, disappoints]▼(to displease by underperforming etc.)
verb
[UK: ˌdɪ.səˈpɔɪnt] [US: ˌdɪ.sə.ˌpɔɪnt]

let down▼(to disappoint)
verb
[UK: let daʊn] [US: ˈlet ˈdaʊn]