the fact that dave drove a hybrid car, as a testimony to his dedication to a green lifestyle, was a deal sealer when christine considered a long term relationship with him
the characteristic, of a person, that seals the deal when considering entering into a relationship
"the fact that dave drove a hybrid car, as a testimony to his dedication to a green lifestyle, was a deal sealer when christine considered a long term relationship with him" What is the definition of "deal sealer"?