It’s a ROT cipher. This is what it means:

I love you. Will you be my boyfriend?

“4” is just the shift. All letters are shifted four characters forwards.

Cipher vs Actual

A → W

B → X

C → Y

D → Z

E → A

…

Z → V

Kneel down and clear the stone of leaves…

*Pupils *arggh *awoo *their *write *gnaw *train *two *carrot *enemy *grandperson *persontake *yawn *thaw *interest *;