Nothing's gonna change my love... What's "gonna"?

[EC]

Nothing's gonna change my love for you. What does "gonna" mean?

"Gonna" is an informal contraction of "going to". So the sentence means: "Nothing is going to change my love for you." There are several other informal contractions like this, especially:

gimme = give me
Gimme your money.

gotta = (have) got a
I've gotta car.
I gotta car.

gotta = (have) got to
I've gotta go now.
I gotta go now.

kinda = kind of
She's kinda cute.

lemme = let me
Lemme go!

wanna = want to
I wanna go home.

wanna = want a
I wanna coffee.

These contractions are used only in very informal speaking. We do not normally use them in "correct" speech or in writing.