In the present economy, business-to-business (B2B) relationships are usually long-termed and characterised by a high degree of mutual pre-existing trust. With the advent of the Internet economy, E- Services marketplaces will provide an infrastructure where B2B relationships will be set up in a highly dynamic fashion. The increased dynamism of the marketplace introduces issues of lack of trust among the market participants, due to the shorter time span of business relationships. The marketplace responds to it by defining admission policy to vet the market participants. Still, the market participants will want to base their negotiation decisions on subjective aspects of trust with regard to other participants. Our model of E-services marketplaces addresses these issues by means of authorization and digital credentials. This paper presents scenarios that highlight trust issues during negotiation within our model. We then produce a first list of requirements that an architecture should satisfy to enhance trust in negotiation within E-Services marketplaces. 16 Pages