To look out for someone is to take care of someone and make sure that they are treated well. So, that expression when translated to Tagalog can be: Iingatan ko si Joyce./ Aalagaan ko si Joyce./ Babantayan ko si Joyce. Sometimes we also say: Ako ang bahala kay Joyce. (that is I'll be responisble for her)

hey, ako ang titingin kay joyce

uy, hanapin ko muna si joyce.