Sorrow can function as both a noun and a verb. As a noun, it refers to a feeling of deep distress or sadness. As a verb, it means to feel deep distress or sadness.
Such is a predicate adjective (also referred to more generally as a subject complement). It modifies Sorrow, which is the subject of this sentence. The order of this sentence is inverted from the typical English, which would be " Her sorrow is such." Therefore, sorrow in this case is an adjective because it modifies a noun.
The word "ruefully" is an adverb. It is used to describe an action done in a way that shows regret or sorrow.
Lamentable is an adjective. The -able ending is used to form adjectives. Other examples are laughable and regrettable.
part of speech
The part of speech for this particular word is a noun.
adverb
what part of speech is work
what part of speech is beneath
This is a quote from the movie The Village. It means that sorrow is unavoidable. That though you might try to find a paradise, where there is nothing to make you sad, you can't escape it, sorrow is part of being human.
Sashay is a verb. It means to walk in an exaggerated, showy manner, often with hip swaying.
An interjection is a part of speech that expresses emotion or surprise and is often used in informal language. It can stand alone or be inserted into a sentence to convey feelings like joy, sorrow, excitement, or pain. Interjections are punctuated with an exclamation mark, comma, or dash to indicate the emotion being expressed.
Adjective