Reproducibility builds trust in machine learning by ensuring that the same code, data, and environment produce the same model results when run multiple times. The process starts by training a model and saving the environment, including software versions and settings. Later, the saved environment is loaded to retrain the model with the same data and parameters. The results are then compared. If the results match, trust is established because the model behaves consistently. If results differ, it signals a change in environment or code, prompting investigation and fixes. This cycle helps maintain reliability and confidence in ML projects.