simply means 'in a simple manner,' conveying straightforwardness. It most often appears as an intensifier, but can also modify adjectives and other adverbs.
rules and use cases of this adverb include using it to emphasize simple processes or situations, to explain why something doesn’t have to be complex, or to signify that a statement is undeniable or straightforward.
1. 'She simply loves to paint.'
2. 'He could simply not leave the party.'
3. 'I simply don’t understand this concept.'
a common mistake is to use 'simply' when what you mean is 'only.' To reiterate, use 'simply' when you want to add emphasis to something, but 'only' when you want to limit or restrict the noun it is modifying.