Summary/Trimmed field in view doesn't include Read More link
did you check " Add a read-more link if output is trimmed. "?

If yes, maybe the problem is, that the text is not trimmed. If you want to have a "read more" link in any case, then you sould add the field "Link" to the view. You can then also enter your custom text, e.g. "details..." instead of "read more" etc.