こととて

Because; since. こととて presents a circumstance as a reason, often to explain a mistake or inconvenience and ask for understanding.

こととて is formal and somewhat old-fashioned, occurring chiefly in writing and polite apologies. Compared with ものだから and もので, it gives an explanation a more elevated tone; unlike ゆえに, it commonly frames the reason as grounds for understanding or forgiveness.

• ものだからN2「ものだから」also explains an excusable reason, but it is colloquial and has a nuance of making excuses; beyond apologies, it is also used to explain a less-than-ideal result or to set out the circumstances before making a request. Nouns take 「な」, whereas 「こととて」takes 「の」.
• ものでN1「もので」is likewise used for excuses and apologies, but it is neutral in register, common in everyday speech, and can also be said as 「もんで」. Nouns and な-adjectives take 「な」 rather than 「の」, and when apologizing the meanings are close, but 「こととて」is appropriate only in formal, written contexts.
• ゆえにN1「ゆえに」is also written language for giving a reason, but it stresses the inevitable link between cause and effect and appears mostly in objective writing such as academic papers and legal texts; it can also stand at the start of a sentence to mean 'therefore'. 「こととて」, by contrast, mostly explains an excusable reason and often carries the nuance of apologizing and asking for understanding.
• 手前N2「手前」expresses that, out of consideration for someone, or because one has already said or done something, one finds it awkward to act otherwise or has no choice but to do so, for the sake of face; its register is neutral. 「こととて」explains an excusable reason to win understanding and sounds archaic, so the two cannot be interchanged.
• とあってN1「とあって」also expresses a reason, but the first clause is a special situation such as a holiday or a celebrity showing up, and the second clause objectively describes the scene that results; it is not used to apologize or ask for forgiveness. Nouns attach directly to 「とあって」 without 「の」, and the two generally cannot be interchanged.
• ことだからN2「ことだから」infers from one's knowledge of the usual behavior of a person (or organization) one knows well that they will inevitably act a certain way, often pairing with 「きっと」 or 「はずだ」; its register is neutral. 「こととて」instead explains an excusable reason in apology, so the two cannot be interchanged.

ものだから and もので can also offer excuses but are less elevated; ゆえに states a cause more neutrally. 手前 suggests an obligation arising from one's position or concern for appearances, とあって highlights a notable circumstance, and ことだから typically predicts behavior from what is known about someone.