I know that we recite bismillah two time in surah namal but i want to know that what is the reason behind reciting second time.
إنه من سليمان وإنه بسم الله الرحمن الرحيم
ألا تعلوا علي وأتوني مسلمين
Indeed, it is from Solomon, and indeed, it reads: 'In the name of Allah, the Entirely Merciful, the Especially Merciful,
Be not haughty with me but come to me in submission [as Muslims].'
Basically the letter begins with Bismillah, and we are repeating the contents of the letter.