What if we accidentally break the mangalvar Hanumaan vrat by the way of eating some sweets? How can we ask for forgiveness or is it an unforgiving act?
Sri Hanuman is the greatest devotee of Bhagavan Sri Ramachandra. So His character must reflect the qualities of Bhagavan Sri Rama.
In Ramayana(yuddha-kanda,18/33) Sri Rama says
sakrid eva prapannaaya tava asmi iti cha yaachate/ abhyam sarvabhutebhyo dadaami etad vratam mama, meaning whoever surrenders to my just by saying 'I am yours' ONLY ONCE, is ever protected by Me.This is My mission.
Being 'Mangala-Murati' Himself, a great tapasvin and eternal servant of such a kind-hearted Master, Hanumanji must be full of forgiveness.Sri Krishna describes the nature of a true devotee in Gita as
12.13 He who is not hateful towards any creature, who is friendly and compassionate, who has no idea of 'mine' and the idea of egoism, who is the same under sorrow and happiness, who is forgiving;
Bhagavan is 'bhava-graahi' and so He listens to our heart's prayer.To err is humane and so if we apologige sincerely, He is bound to forgive all our faults. We should never think Hanumanji as unforgiving because He is eternally dedeicated to someone Who is Forgiveness personified.