Synonyms of the word 
RIGHTFULLY → TRULY
rightfully
- adv. In accordance with what is right or just; fairly.
- adv. Rightly, correctly.
truly
- adv. In accordance with the facts; truthfully, accurately.
- adv. Honestly, genuinely, in fact, really.
- adv. Very.
If you are interested in words, visit the following sites :
- wiktionary.org/rightfully For complete definition of a word
- 1word.ws/rightfully to play with words, suffixs, prefixs, etc.