Final answer:
Shila's statement in indirect speech expresses her inability to come due to illness and her assurance to start as soon as she is able.
Step-by-step explanation:
Shila's direct speech is, “I am unable to come just now as I am ill, but I will certainly start as soon as I am well enough to do so.” The dialogue in indirect speech would be: Shila said that she was unable to come right then because she was ill, but assured that she would certainly start as soon as she was well enough to do so.