Breakdown of Доставка от этого отправителя всегда быстрая.
этот
this [f: эта, n: это]
всегда
always
быстрый
fast, quick
от
from
Questions & Answers about Доставка от этого отправителя всегда быстрая.
Why do we use от here for "from" instead of из?
We use от because the source is a person or entity (a sender). The preposition из is used when something comes "out of" a place, like a city or a box. When you receive a package, a letter, or a message from a person, you must use от.
Why does the word for sender end in -я (отправителя)?
The preposition от requires the word following it to be in the Genitive case. The dictionary form is отправитель, which is a masculine noun ending in a soft sign (-ь). To make it Genitive, that soft sign changes to -я.
Why is it этого instead of этот?
этого is the Genitive masculine form of этот (this). Because the preposition от forces the noun отправителя into the Genitive case, any descriptive words attached to it must also be in the Genitive case to match. Remember that the -г- in этого is pronounced like a "v".
Why is the adjective быстрая feminine when it comes right after the masculine word отправителя?
быстрая (fast) describes the subject of the sentence, доставка (delivery), which is a feminine noun. Even though they are separated by the phrase about the sender, the adjective still has to match the noun it actually describes. Since Russian skips the word "is" in the present tense, the adjective simply sits at the end.