させてもらう details
Examples
get to do (for one's own benefit), framed as receiving permission — a deferential way to announce or request doing something yourself
今日は早く帰らせてもらうね。
kyou wa hayaku kaerasete morau ne.
I'm gonna get to head home early today, if that's okay. casual
この件については、私から説明させてもらいます。
kono ken ni tsuite wa, watashi kara setsumei sasete moraimasu.
Let me be the one to explain this matter. neutral
本日はこれで失礼させていただきます。
honjitsu wa kore de shitsurei sasete itadakimasu.
If you'll allow me, I'll take my leave for today. formal
Formation
causative て-form + もらう（休[やす]ませてもらう）attaches to verb stem (special attachment)
Notes
consent was given or assumed — 有給を取らせてもらいます
announces taking leave as though pre-cleared, softer than a flat 取ります.
Related patterns
Similar
てもらう receives an ordinary favor someone else actively does FOR you; させてもらう receives PERMISSION to do the action yourself, so the favor is being ALLOWED to act, not having the act done — 直[なお]してもらった "had it fixed (by them)" vs 直[なお]させてもらった "got to fix it (myself)".
Lookalikes
Same causative morphology on the surface, but plain させる means someone else MADE or LET the subject act, with the causer as the real actor behind the scenes; させてもらう flips the frame — the SPEAKER is the one doing it, merely presented as having received consent, so reading it as bare causative loses the self-effacing politeness entirely.
Same いただく tail, opposite agent — 手伝[てつだ]っていただく means THEY act and I receive it (they help me), while 手伝[てつだ]わせていただく means I ACT, merely framed as having received permission to (I get to help) — misreading one for the other flips who is actually doing the favor.