A practical english grammar - Vyssaja skola 1978

UNKING VERB + COMPLEMENT + INFINITIVE
Sound symbols

Many adjectives and adverbs after be and other linking verbs are fol­lowed by infinitives and resemble the verbs studied in this chapter.

He was afraid to open the door. (He feared to . . .)

They were eager to come. (They wanted to ...)

I am delighted to go. (I like to ...)

He appears reluctant to admit that. (He hesitates to . . .)

Other expressions that are followed by infinitives are these.

accustomed careful  happy qualified

adequate  competent impatient ready

anxious  fit   inclined sorry

apt   free  pleased sure

ashamed  glad  proud willing