Set adjustsFontSizeToFitWidth to NO and numberOfLines to 0.
numberOfLines Docs
This property controls the maximum number of lines to use in order to
fit the label’s text into its bounding rectangle. The default value
for this property is 1. To remove any maximum limit, and use as many
lines as needed, set the value of this property to 0.If you constrain your text using this property, any text that does not
fit within the maximum number of lines and inside the bounding
rectangle of the label is truncated using the appropriate line break
mode.When the receiver is resized using the sizeToFit method, resizing
takes into account the value stored in this property. For example, if
this property is set to 3, the sizeToFit method resizes the receiver
so that it is big enough to display three lines of text.
You may additionally want to specify the lineBreakMode unless the default UILineBreakModeWordWrap is suitable for what you want.