Update Reason.md

🔰 Grammar/Reason.md

@@ -24,6 +24,14 @@ It is more objective than から: it expresses a situation that exists, and that
 See [[🔰 Particles (2)#Because]].
 It is more subjective than ので: it expresses more personal needs/actions/opinions.
 
+## ことから
+
+Means "based on the fact that". Most formal than から, and puts an emphasis on it being true (objective information).
+
+> [!info] Example
+> {部屋|へや}から{音|おと}がある==ことから==、{誰|だれ}かいるはずです。
+> From the fact that there is sound coming from the room, someone must be there.
+
 ## んです・のです
 
 <div class="usage">