Reverberation distorts speech leading to degradation of speech intelligibility and speech quality. We have been investigating methods to predict speech intelligibility without clean speech which are more difficult than prediction with actual clean speech. In this paper, we attempt to estimate speech intelligibility by simulating the full-reference (F-R) method, substituting the predicted clean speech with clean speech. The correlation between the predicted and measured intelligibility was 0.99945 and the RMSE was 0.00353 with the proposed method.