dis ‧ il ‧ lu ‧ sion /ˌdɪsəˈluːʒ ə n, ˌdɪsɪˈluːʒ ə n/ BrE AmE verb [transitive]
to make someone realize that something which they thought was true or good is not really true or good:
I hate to disillusion you, but I don’t think she’s coming back.
dis ‧ il ‧ lu ‧ sion /ˌdɪsəˈluːʒ ə n, ˌdɪsɪˈluːʒ ə n/ BrE AmE verb [transitive]
to make someone realize that something which they thought was true or good is not really true or good:
I hate to disillusion you, but I don’t think she’s coming back.
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012