Sentence:  A <WSD>happy</WSD> birthday to you, / A <WSD>happy</WSD> birthday to you, / A <WSD>happy</WSD> birthday, dear Roy, / A <WSD>happy</WSD> birthday to you. 
Meaning of the word marked with <WSD> tags:  Having a feeling arising from a consciousness of well-being or of enjoyment; enjoying good of any kind, such as comfort, peace, or tranquillity; blissful, contented, joyous.