Re: 非法不可

「發」 and 「法」 pronounce the same
I think the sentence should be 「我非發不可」
「發」 as in 「發達」(get rich) 

Following the 「非(X)不可」 structure, the phrase 「我非發不可」 means: " I must get rich" it make sense with the following sentence: 「我一定要做到」 (I must make it )

we should not omit   「達」 in 「發達」because there are many common terms  also begin with the character 「發」 , like  「發起」，「發出」，「發夢.」... etc. 

The proper form of this sentence should be 「我非發達不可，我一定要做到」( I must get rich, I have to make it.)