justify
US /ˈdʒʌs.tə.faɪ/
UK /ˈdʒʌs.tə.faɪ/

1.
show or prove to be right or reasonable
:
•
The end does not always justify the means.
•
He tried to justify his actions by explaining the circumstances.
2.
be a good reason for (something)
:
•
Nothing can justify such cruelty.
•
His long hours at work were justified by the promotion he received.