2. Does the court necessarily order the losing party to fully pay the legal cost of the winning party? What are the possible causes that make the court orders differently?
No. Subject to statutory provisions, the court has an unfettered discretion on the matter of costs.
Sometimes, the losing party may well before the commencement of proceedings or trial offer a reasonable settlement offer. If the winning party refuses the proposal and then wins the case at trial but fails to beat the offer, the court may refuse to award costs to the winning party. Furthermore, if there are some unreasonable litigation conducts on the part of the winning party throughout the proceedings (i.e. insist on running some unmeritorious points at trial), the court may exercise discretion to refuse costs (all or part) being awarded to the winning party.