Final answer:
The speaker is implying a regional tradition where serious talk of love is expected to lead to a marriage proposal, reflecting societal norms and the cultural significance of courtship and commitment.
Step-by-step explanation:
The speaker in the line "That's enough. In this part of the country that better be a proposal of marriage," is suggesting a regional tradition that equates serious talk of love or deep commitment with an expectation of a marriage proposal. This implication comes from the cultural context where explicit declarations of love are tied directly to the intention to marry, thereby creating the expectation that any such declaration should be followed by a proposal. The expectation can be understood as a reflection of societal values or norms which may differ between regions, as well as historical or traditional views on the seriousness of courtship and the steps leading up to marriage.