"Di sampingmu."

Translation: Next to you.

[XavierLamb9]

Would "On your side" be correct also?

[dkfour]

I believe so

[donny309620]

An alternative translation: "Beside you".

[Harvey384140]

Beside you sounds OK

[JTJ2Sb]

the suffixes -mu and -ku are possessive identifiers.

[UpzahwvW]

True, they are used that way, but that's not the only way they can be used. They can also be used as prefixes on a verb (indicating the subject of the verb), be attached to the end of a preposition, or even attached to the end of a transitive verb in order to become the object of the verb.