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