"The problem is he is stingy"

Solution 1:

It's perfectly grammatically correct.

The problem is just that: you repeat the word "is".

It's that simple.

It's a commonplace in English, say speechwriting or advertising writing (I mean say for radio or TV voiceovers), that you don't repeat a word in a sentence or, really, in a passage, and particularly not close.

Here you have two "is"s very close, so it sounds awkward. It's that simple.

(AND INDEED, he/his are almost the same word - that's another repeat.)

The solution is this simple:

The problem is this: he's very stingy with money.

The problem is: he's very stingy with money.

or any other combo.

{Note - it goes without saying there are many other situations where, for emphasis, for drama, because you are Winston Churchill, etc, you repeat a word closely. Say ... "May the luck be with the player." .. repeating the "the" sounds cool and dramatic there. But in the example at hand, it's simple: the sentence sounds lousy since you have (indeed two different) close repeats.}

Solution 2:

Not sure how correct it is right now; is it just me or does it need a comma? Like so: "The problem is, he is very stingy with his money."

I know for sure that "The problem is that he is very stingy with his money." is correct though.