Looking on the internet deeply has found these results:

must be he is the most popular phrase on the web.

must be he is gazing 10 results on the web	must be he 110,100 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	Apr 11, 2011 ... My first name must be He Ain't Shit Cause every time I'm in a car bitches be like, " He ain't shit!" I'll be dat, I'll be dat, I'll be dat, I'll be dat My first name must be he ain't shit 'Cause every time I'm in a car bitches be like he ain't shit. I'll bee dat, I'll bee dat, I'll bee dat, I'll bee dat. Yo yo I heard the party �... It must be he who is calling. He is taller than I am tall. (comparitive) To answer the phone: "Is Barbara there?","This is she who is here. Sep 6, 2013 ... So, can I say that the first sentence is erroneous? Would it be correct to write. It must be he with whom you enjoy doing your assignments, not I.

must be he is gazing

10 results on the web

must be he

110,100 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

Apr 11, 2011 ... My first name must be He Ain't Shit Cause every time I'm in a car bitches be like, " He ain't shit!" I'll be dat, I'll be dat, I'll be dat, I'll be dat
My first name must be he ain't shit 'Cause every time I'm in a car bitches be like he ain't shit. I'll bee dat, I'll bee dat, I'll bee dat, I'll bee dat. Yo yo I heard the party �...
It must be he who is calling. He is taller than I am tall. (comparitive) To answer the phone: "Is Barbara there?","This is she who is here.
Sep 6, 2013 ... So, can I say that the first sentence is erroneous? Would it be correct to write. It must be he with whom you enjoy doing your assignments, not I.