Add spaces: IftheUKauthoritieshavereasonstodoubtthesincerityofyourmarriageandcanprovethatitisamarriageofconvenience,theycanwithdrawtherightofresidenceongroundsoffraudorabuseofrights.
If the UK authorities have reasons to doubt the sincerity of your marriage and can prove that it is a marriage of convenience, they can withdraw the right of residence on grounds of fraud or abuse of rights.