事(こと)だからIt is exactly because

Both give reasons, but differ in tone. ことだから emphasizes a reason that is obvious or characteristic, as in 田中さんのことだから大丈夫だろう (Since it’s Tanaka, it should be fine). ものだから is often used to explain or excuse, as in 熱があるものだから休みます (I have a fever, so I’ll take a day off).

Both もの・もん and ことだから can be used to give reasons, but they differ in tone and intent. もの・もん is casual, colloquial, and subjective, used to express personal feelings or justifications, like 'because (A)'. ことだから, on the other hand, has a more objective and emphatic feel, often meaning 'it is precisely because (A) that (B)'. In some contexts, ことだから can also imply 'considering (A), then (B)'.

These phrases are similar in that both express a reason with a degree of certainty, but they differ in specific usage and nuance. なぜなら〜から is used at the beginning of a sentence to provide a reason for something previously said, explicitly saying 'as for why, (A)'. ことだから is used at the end of a phrase with the reason following, conveying 'it is precisely because (A) that (B)'.

からこそ and ことだから are similar in that both can emphatically state a reason. However, ことだから is typically used to make a prediction or assumption based on a person's known behavior or character, e.g. 田中さんのことだからできると思う ('Because it's Tanaka, I think he can do it'). In contrast, からこそ is more broadly used to emphasize a specific reason, e.g. 努力したからこそできた ('I could do it precisely because I worked hard').

ことから and ことだから both express reasons, but differ in usage. ことから explains a fact-based conclusion, e.g. 顔が赤いことから熱があると分かった ('From the fact their face is red, I knew they had a fever'). ことだから gives a reason based on someone's known traits, e.g. 田中さんのことだから、もう宿題は終わっているだろう ('Since we're talking about Tanaka, he's probably finished his assignment already').