The difference between Guts and Insides

Guts is also verb with the meaning: to show determination or courage (especially in the combination guts out).

Insides is also noun with the meaning: guts, intestines, innards.

check bellow for the other definitions of Guts and Insides

Guts as a noun:
Guts as a noun:

The entrails or contents of the abdomen.
Guts as a noun (slang):

Courage; determination.

Examples:

"It must have taken some guts to speak in front of that audience."

"She doesn't take any nonsense from anyone—she's got guts."
Guts as a noun (slang):

Content, substance.

Examples:

"His speech had no guts in it."
Guts as a noun (in the plural):

The essential, core parts.

Examples:

"He knew all about the guts of the business, how things actually get done."
Guts as a noun (slang):

One's innermost feelings.

Examples:

"If you need someone to spill your guts out to, I'm here."

Guts as a verb (informal):

To show determination or courage (especially in the combination guts out).

Examples:

"He gutsed out a 6-1 win."