خَالِدٌ أَمِينٌ. لَا يَخُونُ الْأَمَانَةَ.
Khalid is trustworthy. He does not betray a trust.
The second sentence explains and reinforces the first. Absence of a conjunction therefore does not imply disconnection. One recognized setting for faṣl is such intimate semantic connection that the following sentence serves as clarification or confirmation.
A reader who inserts “wa” between every related sentence confuses grammatical linkage with rhetorical cohesion. The grounds for separation lie in the semantic relation, not punctuation alone.