When they said thejobwouldinvolvetravellingtoParis, thatclinchedit (forher)(= that made hercertainthat shewantedthejob).
Abigproportionofvotersclaimthat theteleviseddebatesbetweencandidatesmay be whatclinchesit for them.
Ajurymemberexplainedthat the thing thatclinchedit for her was that thedefendantdrovethecarknowingit wasstolen.
Welovedthehouseassoonas wesawit, but it was thegardenthatclinchedit.
Isawhim beingmeanto thedogsand thatclinchedit. IknewI had tobreakup with him.
See alsoclinchverb(DECIDE)informal