Service supported by an object is modeled to be a set of methods and quality of service (QoS). In addition to finding a peer which holds a target object, it is critical to discuss what peer is allowed to manipulate the target object in what method. In this paper, we take an acquaintance approach to finding and manipulating objects in P2P overlay networks. An acquaintance peer of a peer p is a peer whose service the peer p know and with which the peer p can directly communicate. If an access request is issued, a peer has to find where a target object exists, how to obtain an access right on the target object, and how to manipulate the target object. In this paper, we discuss ways to obtain results which satisfying an access requests by the cooperation of acquaintances. Acquaintance peers of a peer p may knows different information on target peers since it takes time to propagate change information of the target peers and peers may be faulty. Here, it is critical to discuss how much a peer can trust each acquaintance. We define the trustworthiness of an acquaintance peer in terms of the acquaintance relations among the peers.