Is it obligatory for the questioner to explain a past situation that occurred with his sister on the bus, or should the matter be carried on good faith, taking into consideration that he was a child at the time?

Jealousy over one's honor ( عرض ) is one of the qualities of a believer and a mark of manliness enjoined by Islamic law. The Prophet, peace and blessings be upon him, said: "Indeed, Allah is jealous, and a believer is jealous. Allah's jealousy is aroused when His servant commits what He has forbidden." He also said: "No one is more jealous than Allah, and it is because of His jealousy that He has forbidden indecencies, both outward and inward."