(n.) The quality of being sentimental; the character or behavior of a sentimentalist; sentimentality.

anticlimax bleeding heart cloyingness comedown goo hearts-and-flowers heaviness heaviness of heart heavy heart heavyheartedness maudlinness mawkishness mush mushiness namby-pamby namby-pambyism namby-pambyness nostalgia nostomania oversentimentalism oversentimentality pathos romanticism sadheartedness sadness sentiment sentimentalism sentimentality slop sloppiness slush soap opera sob story sweetness and light tearjerker