1. When one is offered a gift, one should not reject it as this will dishearten the person who had offered the gift. However, if there is a valid reason to reject the gift, (e.g. the gift is being given by a non-mahram girl to a boy or vice-versa, or a bribe is given in the pretext of a gift, etc.), then one should not accept the gift.
قال عمر بن عبد العزيز: كانت الهدية في زمن رسول الله صلى الله عليه وسلم هدية، واليوم رشوة (صحيح البخاري، باب من لم يقبل الهدية لعلة)
Hazrat Umar bin Abdul Aziz (rahimahullah) once mentioned, “The gifts given in the era of Rasulullah (sallallahu ‘alaihi wasallam) were gifts (given with the intention of engendering love), but today (in many cases) a gift is given as a bribe.”