Hired to work for the summer with 〜ことになっている

Grammar Explanation: Past decision still in effect with 〜ことになっている

Rinko (Yamato) interviews for a summer job at her favorite cake shop. Following the interview, she is hired and is set to start work the next day. She’s excited at the various new techniques she’ll learn that she’ll use to make various sweets for her boyfriend, Takeo.

凛子(りんこ):: 「それがいちばん楽(たの)しみかも」; “I think that's what I'm most looking forward to.”
猛男(たけお):: 「大和(やまと)うれしそうだな」; “Yamato looks happy.”; 「ずっと好(す)きだったケーキ屋(や)で働(はたら)けることになってよかった」; “I'm glad it's arranged that she'll be able to work at her most favorite cake shop.”; Literal: “I'm glad it has become the thing that she can work at the cake shop she has always liked.”

Key Points

1ことになって = “it’s been decided/arranged that…” (て-form)

ことになっている means “it has been decided/arranged that…” (a past decision still in effect).
It often suggests the decision was made through external circumstances (like getting hired), not purely personal choice.
ことになって is the て-form, used here to connect to よかった (“I’m glad”).

2Potential form

The potential form 働(はたら)ける (“able to work”) emphasizes the opportunity to work there (she can/is able to work there).

3Why て-form here

The て-form ことになって connects the clause to よかった.
This creates a single thought: “Because it turned out this way, I’m glad.”