Reasonably explain, definition
Reasonably explain, means a plausible statement of circumstances indicating that the failure to file within the appropriate deadline was not deliberate or intentional but, instead, was the result of inadvertence, mistake, or mischance; negligent forgetfulness may suffice, but an intentional decision to delay will not. Castillo v. State, 369 S.W.3d 196, 202 (Tex.Cr.App. 2012).