Having the intention or effect of making angry people calm.(Oxford)
Showing willingness to end a disagreement, or trying to make someone less angry.(Cambridge)
His tone was quite conciliatory. (Oxford)
The Deputy Prime Minister tried to sound conciliatory towards the rebels.(Cambridge)
tone was quite conciliatory
conciliatory towards
Mollifying
Peaceable
Antagonistic
Refusing
Conciliate
Conciliation