Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I must fiance you must fiance he must fiance we must fiance you must fiance they must fiance
V-ing form
I must be fiancing you must be fiancing he must be fiancing we must be fiancing you must be fiancing they must be fiancing
Perfect
I must have fianced you must have fianced he must have fianced we must have fianced you must have fianced they must have fianced
V-ing perfect
I must have been fiancing you must have been fiancing he must have been fiancing we must have been fiancing you must have been fiancing they must have been fiancing
Negation
Simple form
I must not fiance you must not fiance he must not fiance we must not fiance you must not fiance they must not fiance
V-ing form
I must not be fiancing you must not be fiancing he must not be fiancing we must not be fiancing you must not be fiancing they must not be fiancing
Perfect
I must not have fianced you must not have fianced he must not have fianced we must not have fianced you must not have fianced they must not have fianced
V-ing perfect
I must not have been fiancing you must not have been fiancing he must not have been fiancing we must not have been fiancing you must not have been fiancing they must not have been fiancing
Interrogative form
Simple form
must I fiance? must you fiance? must he fiance? must we fiance? must you fiance? must they fiance?
V-ing form
must I be fiancing? must you be fiancing? must he be fiancing? must we be fiancing? must you be fiancing? must they be fiancing?
Perfect
must I have fianced? must you have fianced? must he have fianced? must we have fianced? must you have fianced? must they have fianced?
V-ing perfect
must I have been fiancing? must you have been fiancing? must he have been fiancing? must we have been fiancing? must you have been fiancing? must they have been fiancing?
Interro-negative form
Simple form
must I not fiance? must you not fiance? must he not fiance? must we not fiance? must you not fiance? must they not fiance?
V-ing form
must I not be fiancing? must you not be fiancing? must he not be fiancing? must we not be fiancing? must you not be fiancing? must they not be fiancing?
Perfect
must I not have fianced? must you not have fianced? must he not have fianced? must we not have fianced? must you not have fianced? must they not have fianced?
V-ing perfect
must I not have been fiancing? must you not have been fiancing? must he not have been fiancing? must we not have been fiancing? must you not have been fiancing? must they not have been fiancing?