sweeten
US /ˈswiː.tən/
UK /ˈswiː.tən/

1.
make sweet or sweeter in taste
:
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You can sweeten your coffee with honey instead of sugar.
•
Add a little sugar to sweeten the sauce.
2.
make more pleasant or acceptable
:
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The company offered a bonus to sweeten the deal.
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He tried to sweeten the news by adding a positive spin.