What basis an employer can find a suitable employee for business development manager position?

Business development manager is responsible for developing the business, identity new opportunities to increase profit and also should build strong relationships. Accordingly you need to look for a candidate with interpersonal skills, negotiation and communication skills , sales knowledge , business knowledge and research and analysis skills.

I agree with Samah Al-Ja'abari  

The seeking Employer has a list of priorities which he has already noted down. And which ever candidates fall under same line as per employer priorities and desires will be shortlisted then filtered for final interview and whoever wins it is appointed. Again the Employee desires and conditions too should be met for closing the deal for working for the employer.

Business development manager (BDM) is responsible to identify sales leads, pitch goods or services to new clients. BDM is responsible for planning and overseeing new marketing initiatives for local or new markets. BDM is responsible for identifying new business opportunities, new partnerships, new ways to reach existing markets, researching organizations and individuals to identify new leads and potential new markets. BDM is responsible for identifying new clients and exploring new markets in order to generate new lead flows.